- Signs You’re Too Sick to Work Out – Working Out
- 7 Signs You're Too Sick to Workout
- 4 Symptoms That SHOULDN'T Mess With Your Workout
- Exercising with a Cold: When Is it OK?
- If Your Symptoms Are Above the Neck
- If Your Symptoms Are Below the Neck
- Are Some Workouts Better Than Others When You're Sick?
- When Are You Too Sick to Work Out?
- The Need-to-Know
- The Takeaway
- Working Out While Sick: Good or Bad?
- Mild Cold
- Stuffy Nose
- Mild Sore Throat
- Productive or Frequent Cough
- Stomach Bug
- Flu Symptoms
- Exercise when sick: Should you sweat it out? Or rest and recover?
- The immune system: A quick and dirty intro
- The innate and adaptive immune response
- Should you exercise while sick?
- What about “working out”?
- How exercise affects the immune system
- Exercise, stress, and immune function
- The role of stress
- Sickness and stress
- Overtraining and infection
- Learning from cancer & HIV
- Other factors affecting immunity
- Training age
- Textbook guidelines for exercising while sick
- Exercising When Sick: A Good Move?
Signs You’re Too Sick to Work Out – Working Out
During cold, flu, or allergy season, it's all too easy to write off exercise until you feel 100 percent — an approach that can, over time, deter you from reaching your fitness goals. While you should A-L-W-A-Y-S listen to your body, and take days off whenever you feel it, not all symptoms actually warrant inactivity.
Before you collect your get-out-gym-free card, consider these guidelines from Gregory Stewart, M.D., team physician for Tulane Athletics, and Stephen Rice, M.D., director of the Jersey Shore Sports Medicine Center in Neptune, New Jersey, and a spokesperson for the American College of Sports Medicine:
7 Signs You're Too Sick to Workout
1. You feel light-headed and dizzy. Typically, standing makes the blood valves in your legs contract, which regulates your blood pressure and keeps your brain clear.
But when a cold, irregular heartbeat or recent concussion leaves you under the weather, this process could be a bit off, and working out can make you feel faint and disoriented — a dangerous combo at the gym, and a surefire way to make things worse.
2. You're achy, and you're already sweating or shivering.
They're all signs you could have a fever, a defense mechanism your body uses to fight infection, which actually takes a lot of effort.
When you hit the gym with a fever, though, it's working out double-time: It tires you out and more difficult for your body to fend off whatever is getting you down.
3. You're nauseous or vomiting. While fresh air may help the nausea, moving around could bring up your last meal right in the middle of spin class. Totally not worth it if you intend to show your face at the gym ever again.
4. You look lethargic and pale. Not everyone is all bright-eyed and bushy-tailed before they hit the gym. But if you feel so-so and have lost all your color, take the hint and give yourself a break.
5. Your mouth is particularly dry. Fending off infection depletes your fluids — it's kinda sweating when you do a tough workout — and dry mouth can be the first sign of dehydration. Because you're already prone to this when you're sick, you'd be smart to skip your sweat session and have a drink ( tea, not booze) instead.
6. You can't put your finger on it, but you just don't feel right. Unless you're suffering from laziness and severe lack of motivation, listen to your body. It's saying, “Save your energy and make an effort to feel better!” So go on, take it easy!
7. You feel a cold coming on. In the long term, working out can strengthen your immune system. However, even short workouts can temporarily weaken it.
When you're on your game, you don't feel the effects of this post-workout dip.
But when you're already feeling crappy, working out can make you even more vulnerable to illness — especially if you work out in a germ-filled gym.
4 Symptoms That SHOULDN'T Mess With Your Workout
Only you know your physical limits. Use these guidelines to inform your decision — but no sweat if you decide to skip the gym, anyhow.
1. Your nose is kinda stuffed up, but you feel fine otherwise. If you only feel gross above the neck (i.e., you have a head cold, headache, or nasal congestion without a fever or aches) working out is A-OK. And if you're coughing up a little bit of phlegm from your chest, but feel good otherwise? Hit the gym; you should be fine.
2. Cramps. Good news: Exercise triggers the release of feel-good endorphins and increases blood flow, which actually alleviates cramps! Sorry, not sorry.
3. You puked this morning, but you feel much better now. Sometimes when your body responds to illness by triggering an isolated spell of vomiting, it gets rid of whatever was messing with your system. As long as you're well hydrated (i.e., your urine is clear, and there's a lot of it), there's no need to skip your workout.
4. You feel meh, but you're super-antsy. You know your body better than anyone. If skipping a workout will mess with your mood, don't deprive yourself. Instead, go with an activity you do regularly, and give it about 70 percent of your regular effort. Walking, yoga, or a little light stretching outdoors could be just what you need to feel better.
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Exercising with a Cold: When Is it OK?
For the first time ever, you've been sticking to a consistent workout routine.
You're hitting the gym in the evenings, no matter what happy hour plans your coworkers goad you with. You're even managing morning sessions — and, even more impressively, you're staying true to the meal plan you committed to at the start of your program.
With this momentum, nothing will stop you from achieving your goals — until you start feeling that tickle in your throat. Then comes the coughing, then sneezing, and then you can't sleep. You've caught a cold, and now that it's here, your gains are in jeopardy. Do you push through the discomfort, or shut down your progress to recover?
Colds and other minor illnesses are bound to throw you off your game at one point or another, since the CDC estimates that US adults catch a cold two to three times a year. Since you're going to have to deal with the symptoms either way, you should have a game plan to decide when it's serious enough to pause your routine..
If you’re sick but still want to work out, ask yourself one question: Are your symptoms above or below your neck?
If Your Symptoms Are Above the Neck
For symptoms isolated above the neck — think the congestion, sore throat, or sneezing of a common cold — you can continue light or moderate activity.
Try taking a non-drowsy decongestant to help fight your symptoms. If your energy level feels good enough, you can head to the gym: just dial back the intensity of your workout.
Aleksej SarifulinGetty Images
Think of your fellow gym-goers, too: Make sure you wash your hands, wipe down your equipment after use, and cough or sneeze into your shoulder rather than your hand to reduce the risk of spreading your germs to others.
If you start to feel worse, take down your intensity a notch or end your workout early, so you don’t make your sickness worse. And get back to your normal routine gradually: Diving back into intense exercise—especially when you’re not feeling 100 percent—can actually suppress your immune system, which can slow your recovery.
If Your Symptoms Are Below the Neck
If your symptoms are below the neck — coughing, shortness of breath, chest tightness, nausea, vomiting, or diarrhea — or system-wide, fever or joint aches — you should flat-out skip your workout.
Moyo StudioGetty Images
These symptoms can point to a more serious infection.
Plus, not only will you ly not be able to tolerate your normal routine, but attempting it could also put you at risk for respiratory problems, dehydration, dizziness, or even passing out.
Are Some Workouts Better Than Others When You're Sick?
The type of exercise you perform while sick doesn't matter as much as the intensity. For instance, if you were set to do some sprints, try jogging instead. Or if you’re lifting that day, dial back your weight and up your reps—just make sure to take longer rest breaks than usual between your sets.
If you're a fitness class junkie, it may be a good idea to skip the group workouts for a solo session. As previously mentioned, you'll want to avoid spreading germs by sneezing in the middle of a crowded class.
Drew Watson, M.D., M.S., is a physician in the department of orthopedics and rehabilitation’s division of sports medicine at the University of Wisconsin School of Medicine and Public Health.
When Are You Too Sick to Work Out?
Your Foolproof Guide to Treating and Preventing the Flu
Getting sick is a part of life. It’s gotten us school, ruined plans for that big party, and kept us up in the middle of the night. In fact, most adults average two or three respiratory infections per year.
But the fact remains: Sometimes you’ve got obligations that can’t wait. And if getting healthier in the New Year is one of those, it can feel a big setback to be sidelined by a cold as soon as you’ve adopted your new health-focused groove.
In general, if you’ve got a little cold, it’s best to scale back, decreasing both the intensity and duration of the workout, says Lipi Roy, M.D., an internist at Massachusetts General Hospital and instructor at Harvard Medical School. But there are also instances when you should take time off completely. Here’s how to know the difference.
Remember this easy rule: If your symptoms occur around your neck and above, it’s OK to do a light workout. If you’re sick below the neck, stay home.
We’ll provide a few more details: If you have a common cold or mild upper respiratory symptoms— a runny or stuffed-up nose—it’s generally all right to work out.
“In fact, there’s evidence that a light run followed by a lukewarm or hot shower may actually help clear congestion,” says Harry Pino, Ph.D., the senior exercise physiologist at NYU Sports Performance Center.
Current perspective on exercise immunology. Nieman DC. Current sports medicine reports, 2003, Nov.;2(5):1537-890X.
But the same isn’t true if you’ve got body aches, chest congestion, abdominal pain, or profound weakness, Roy says. In that case, stay home, drink plenty of fluids, and binge watch Jessica Jones on Netflix. (Editor’s note: Science has yet to prove a correlation between accelerated flu recovery and Netflix, but proceed.)
There’s also one exception to our ‘above the neck’ rule: a fever. “If you’ve got a fever, avoid working out at all,” Roy says.
Since a fever raises your body’s core temperature, and working out can also increase your body temperature, it’s not a good combination, Pino says. Plus, there’s the issue of dehydration.
With the flu or a fever, it’s easy to get dehydrated—don’t make it worse by taxing your body with burpees or a spin class.
Even after your fever has broken or you’ve recovered from a bad illness, Roy suggests avoiding workouts for the next 24 to 48 hours. And when you do get back into it, do not start with an intense workout—ramp up slowly, she says.
Aside from being sick and working out, keep in mind that regular, moderate exercise can actually help improve your immune system—and therefore help prevent future illnesses.Exercise and the Regulation of Immune Functions.
Simpson RJ, Kunz H, Agha N. Progress in molecular biology and translational science, 2015, Sep.;135():1878-0814. The key here is to keep it moderate and recreational.
When you take it to the next level, things can get a little more complicated.
“Any time that you are performing [athletically] at high levels, you compromise your immune system,” Pino says. Ever heard of the marathon sniffles? You run a marathon, and then you’re sick for the next week.
That’s because when performing at high levels, or when you put extra stress on your body, your immune system is temporarily compromised.Strategies to enhance immune function for marathon runners : what can be done? Akerström TC, Pedersen BK.
Sports medicine (Auckland, N.Z.), 2007, Jul.;37(4-5):0112-1642. Immunity in athletes. Mackinnon LT. International journal of sports medicine, 1997, Jun.;18 Suppl 1():0172-4622.
Think of it as too much of a good thing: Just the right amount of exercise gives you a boost, and an excessive amount of strenuous training can have the reverse effect.
“If you’re not feeling well, this is Mother Nature saying, ‘Take it easy,’” Roy says. In other words, even if you’ve technically got the OK to hit the treadmill, you might end up recovering faster and simply feeling better if you take a day or two off to focus on drinking lots of fluids, eating healthy meals, and getting some extra sleep.
If you do choose to go to the gym, take care to sanitize the equipment before and after your workout to minimize the spread of germs, Roy says. (Most gyms have sanitizing wipes available throughout the space. If your gym doesn’t, consider bringing hand sanitizer with you.)
“It’s really important to keep your immune system high to reduce your risk [of getting sick],” Roy says. And since stress, smoking, poor sleep, and nutrition can all contribute to a suppressed system, it’s a good idea to focus on building up before you start challenging your body with a new workout routine.
Originally published December 2011. Updated January 2016.
Working Out While Sick: Good or Bad?
Written by Jillian Kubala, MS, RD on January 23, 2018
Engaging in regular exercise is an excellent way to keep your body healthy.
In fact, working out has been shown to decrease the risk of chronic diseases diabetes and heart disease, help keep weight in check and boost the immune system (1, 2, 3).
While there is no doubt that exercise plays an important role in health, many people wonder if working out while sick will help or hinder their recovery.
However, the answer isn’t black and white.
This article explains why sometimes it’s ok to work out when you are sick, while other times it’s best to stay home and rest.
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A speedy recovery is always the goal when you are sick, but it can be hard to know when it’s ok to power through with your normal gym routine and when it’s best to take a few days off.
Exercise is a healthy habit, and it’s normal to want to continue working out, even when you’re feeling under the weather.
This can be perfectly fine in certain situations but also detrimental if you are experiencing certain symptoms.
Many experts use the “above the neck” rule when advising patients on whether to continue working out while sick.
According to this theory, if you are only experiencing symptoms that are above your neck, such as a stuffy nose, sneezing or an earache, you’re probably ok to engage in exercise (4).
On the other hand, if you are experiencing symptoms below your neck, nausea, body aches, fever, diarrhea, productive cough or chest congestion, you may want to skip your workout until you feel better.
A productive cough is one in which you’re coughing up phlegm.
Summary Some experts use the “above the neck” rule to determine whether working out while sick is safe. Exercise is most ly safe when symptoms are located from the neck up.
Working out with the following symptoms is most ly safe, but always check with your doctor if you are unsure.
A mild cold is a viral infection of the nose and throat.
Though symptoms vary from person to person, most people who have a cold experience a stuffy nose, headache, sneezing and mild cough (5).
If you have a mild cold, there’s no need to skip the gym if you have the energy to work out.
Although, if you feel that you lack the energy to get through your normal routine, consider reducing the intensity of your workout or shortening its duration.
While it’s generally ok to exercise with a mild cold, keep in mind that you might spread germs to others and cause them to become ill.
Practicing proper hygiene is a great way to prevent spreading your cold to others. Wash your hands frequently and cover your mouth when you sneeze or cough (6).
An earache is a sharp, dull or burning pain that can be located in one or both ears.
Though ear pain in children is commonly caused by infection, earache in adults is more commonly caused by pain occurring in another area, such as the throat. This pain, which is known as “referred pain,” then transfers to the ear (7, 8).
Ear pain can be caused by sinus infections, sore throat, tooth infection or changes in pressure.
Working out with an earache is considered safe, as long as your sense of balance is not affected and an infection has been ruled out.
Certain types of ear infections can throw you off balance and cause fevers and other symptoms that make working out unsafe. Make sure you don’t have one of these ear infections before beginning exercise (9).
However, most earaches can just be uncomfortable and cause a feeling of fullness or pressure in the head.
Though exercise is ly safe when you have an earache, try to avoid exercises that put pressure on the sinus region.
Having a stuffy nose can be frustrating and uncomfortable.
If it’s associated with a fever or other symptoms a productive cough or chest congestion, you should consider taking some time off from working out.
However, it’s ok to work out if you are only experiencing some nasal congestion.
In fact, getting some exercise may help open up your nasal passages, helping you breathe better (10).
Ultimately, listening to your body to determine if you feel well enough to exercise with a stuffy nose is the best bet.
Modifying your workout to accommodate your energy level is another option.
Going for a brisk walk or bike ride are great ways to stay active even when you aren't feeling up to your usual routine.
Always practice proper hygiene at the gym, especially when you have a runny nose. Wipe down equipment after you’ve used it to avoid spreading germs.
Mild Sore Throat
A sore throat is usually caused by a viral infection the common cold or flu (11).
In certain situations, when your sore throat is associated with a fever, productive cough or difficulty swallowing, you should put exercise on hold until a doctor tells you it’s ok.
However, if you are experiencing a mild sore throat caused by something a common cold or allergies, working out is ly safe.
If you are experiencing other symptoms that are often associated with a common cold, such as fatigue and congestion, consider reducing the intensity of your normal exercise routine.
Reducing the duration of your workout is another way to modify activity when you feel well enough to workout but don’t have your usual stamina.
Staying hydrated with cool water is a great way to soothe a sore throat during exercise so you can add activity into your day.
Summary It’s most ly ok to work out when you are experiencing a mild cold, earache, stuffy nose or sore throat, as long as you aren’t experiencing more serious symptoms.
While exercising is generally harmless when you have a mild cold or earache, working out when you are experiencing any of the following symptoms is not recommended.
When you have a fever, your body temperature rises above its normal range, which hovers around 98.6°F (37°C). A fever can be caused by many things, but it’s most commonly triggered by a bacterial or viral infection (12, 13).
Fevers can cause unpleasant symptoms weakness, dehydration, muscle aches and loss of appetite.
Working out while you’re feverish increases the risk of dehydration and can make a fever worse.
Additionally, having a fever decreases muscle strength and endurance and impairs precision and coordination, increasing the risk of injury (14).
For these reasons, it’s best to skip the gym when you have a fever.
Productive or Frequent Cough
An occasional cough is a normal response to irritants or fluids in the body’s airways, and it helps keep the body healthy.
However, more frequent episodes of coughing can be a symptom of a respiratory infection a cold, flu or even pneumonia.
While a cough associated with a tickle in the throat isn't a reason to skip the gym, a more persistent cough can be a sign you need to rest.
Although a dry, sporadic cough may not impair your ability to perform certain exercises, a frequent, productive cough is reason to skip a workout.
A persistent cough can make it difficult to take a deep breath, particularly when your heart rate rises during exercise. This makes you more ly to become short of breath and fatigued.
A productive cough that brings up phlegm or sputum may be a sign of infection or another medical condition that requires rest and should be treated by a doctor (15).
Furthermore, coughing is one of the main ways illnesses the flu are spread. By going to the gym when you have a cough, you’re putting fellow gym-goers at risk of being exposed to your germs.
Illnesses that affect the digestive system, such as the stomach flu, can cause serious symptoms that make working f-limits.
Nausea, vomiting, diarrhea, fever, stomach cramping and decreased appetite are all common symptoms associated with stomach bugs.
Diarrhea and vomiting put you at risk of dehydration, which physical activity worsen (16).
Feeling weak is common when you have a stomach ailment, increasing the chance of injury during a workout.
What’s more, many stomach illnesses the stomach flu are highly contagious and can be easily spread to others (17).
If you are feeling restless during a stomach illness, light stretching or yoga at home are the safest options.
Influenza is a contagious illness that impacts the respiratory system.
The flu causes symptoms fever, chills, sore throat, body aches, fatigue, headache, cough and congestion.
The flu can be mild or severe, depending on the level of infection, and may even cause death in serious cases (18).
Although not every person who gets the flu will experience a fever, those who do are at an increased risk of dehydration, making working out a bad idea.
Though the majority of people recover from the flu in less than two weeks, choosing to engage in intense workouts while sick may prolong the flu and delay your recovery.
This is because engaging in higher-intensity activity running or a spin class temporarily suppresses the body’s immune response (19).
Plus, the flu is a highly contagious virus that is spread primarily through tiny droplets people with the flu release into the air when they talk, cough or sneeze.
If you are diagnosed with the flu, it’s best to take it easy and avoid exercise while you’re experiencing symptoms.
Summary If you are experiencing symptoms fever, vomiting, diarrhea or a productive cough, taking time off from the gym may be the best option for both your own recovery and the safety of others.
Many people are anxious to get back to the gym after recovering from an illness — and for good reason.
Regular exercise can reduce your risk of becoming sick in the first place by boosting your immune system (20, 21).
However, it’s important to let your body completely recover from an illness before returning to your exercise routine, and you shouldn't stress even if you are unable to work out for an extended period of time.
While some people worry that a few days off from the gym will set them back and cause a loss of muscle and strength, that’s not the case.
Many studies show that for most people, muscle loss begins after approximately three weeks without training, while strength starts to decline around the 10-day mark (22, 23, 24, 25).
As symptoms subside, gradually begin introducing more physical activity into your day, being careful not to overdo it.
On your first day back to the gym, begin with a low-intensity, shorter workout and be sure to hydrate with water while exercising.
Remember, your body may be feeling weak, especially if you are recovering from a stomach illness or the flu, and it’s important to pay attention to how you are feeling.
If you are questioning whether you can safely work out while recovering from being sick, ask your doctor for advice.
Additionally, even though you may be feeling better, keep in mind that you might still be able to spread your illness to others. Adults are able to infect others with the flu up to seven days after first experiencing flu symptoms (26).
Although getting back to the gym after an illness is beneficial for your overall health, it is important to listen to your body and doctor when deciding whether you are well enough for more intense activity.
Summary Waiting until symptoms completely subside before gradually getting back into your workout routine is a safe way to return to exercise after an illness.
When experiencing symptoms diarrhea, vomiting, weakness, fever or a productive cough, it’s best to rest your body and take some time off from the gym to recover.
However, if you caught a mild cold or are experiencing some nasal congestion, there’s no need to throw in the towel on your workout.
If you are feeling well enough to work out but lack your usual energy, reducing the intensity or length of your workout is a great way to stay active.
That said, to stay healthy and safe when you’re sick, it is always best to listen to your body and follow your doctor’s advice.
Exercise when sick: Should you sweat it out? Or rest and recover?
Everybody gets sick. But it’s tough to know what to do about it; do you exercise when sick or not?
Should you “sweat it out”? Or get some rest instead?
In this article we clear up the confusion. Next time you come down with the flu or a cold, you’ll know what to do.
- Want to see our visual guide? Check out the infographic here…
Your friendly neighborhood gym. You’re warmed up and ready for a great workout.
Then, all the sudden, Mr. Sneezy walks by. Coughing, sniffling, and heavy mouth-breathing. He’s spraying all over the benches and mats.
“Dude, shouldn’t you just stay home and rest?” you’re thinking.
(And, while you’re at it, stop sharing those nasty germs?)
But maybe Mr. Sneezy’s onto something. Maybe he’ll be able to sweat the sickness his system, boosting his immune system along the way.
What’s the right approach? Let’s explore.
The immune system: A quick and dirty intro
Every single day, bacteria, viruses, fungi, and parasites come at us. Folks, it’s a germ jungle out there!
The most common invaders are upper respiratory tract invaders, or URTI’s. Yep, I’m talking about
- throat infections, and
- middle ear infections.
Luckily, our immune system has got a plan. When faced with foreign attack, it works hard to defend us. Without the immune system, we’d never have a healthy day in our lives.
Our immune cells originate in our bone marrow and thymus. They interact with invaders through the lymph nodes, the spleen, and mucus membranes.
This means they first make contact in your mouth, gut, lungs, and urinary tract.
The innate and adaptive immune response
Our innate (natural) immune system is our non-specific first line of defense.
- physical/structural barriers ( the mucous lining in nasal passages),
- chemical barriers ( our stomach acids), and
- protective cells ( our natural killer ‘NK’ cells, white blood cells that can destroy harmful invaders).
This immune system develops when we’re young.
Interestingly, women tend to have a stronger overall innate immune response. (Maybe this is why they often do better than men when it comes to colds. But they suffer more often from autoimmune diseases.)
Then there’s the adaptive (acquired) immune system.
This is a more sophisticated system composed of highly specialized cells and processes. It kicks in when the innate immune system is overcome.
The adaptive immune system helps us fight infections by preventing pathogens from colonizing and by destroying microorganisms viruses and bacteria.
Cue the T and B cells. These specialized white blood cells mature in the thymus and bone marrow, respectively. And believe it or not, they actually have a kind of memory.
It’s this memory that makes them so effective. Once they “recognize” a specific pathogen, they mobilize more effectively to fight it.
This is what we mean when we talk about “building immunity.”
Ever wondered why kids get sick with viruses more often than adults? It’s because they haven’t had as much exposure so their adaptive immune systems are less mature.
What’s more, the acquired immune response is the basis for vaccination. Subject your body to a tiny dose of a pathogen, and it will know what to do when confronted with a bigger dose.
Should you exercise while sick?
Let’s get one thing clear from the start: there’s a difference between “working out” and “physically moving the body.”
A structured workout routine — one where you’re breathing heavily, sweating, working hard, and feeling some discomfort — awakens a stress response in the body.
When we’re healthy, our bodies can easily adapt to that stress. Over time, this progressive adaptation is precisely what makes us fitter and stronger.
But when we’re sick, the stress of a tough workout can be more than our immune systems can handle.
Still, there’s no reason to dive for the couch the minute you feel the sniffles coming on. Unless you’re severely shape, non-strenuous movement shouldn’t hurt you — and it might even help.
What do I mean by “non-strenuous movement”?
Well, it might include:
- walking (preferably outdoors),
- low intensity bike riding (again, outdoors),
- practicing T’ai Chi.
In fact, all of these activities have been shown to boost immunity.
They aren’t intense enough to create serious immune-compromising stress on the body. Instead, they often help you feel better and recover faster while feeling under the weather.
That’s why Dr. Berardi often recommends low intensity non-panting “cardio” when suffering from colds. Done with minimal heart rate elevation, preferably outside, these activities seem to offer benefits.
What about “working out”?
Non-strenuous movement and purposefully working out are different.
Plus, as you probably know, not all workouts are created equal. There are low intensity workouts and high intensity workouts — and all sorts of workouts in between.
But what’s low to one person might be high to another. So how can you decide what level of intensity counts as strenuous?
Let your own perceived level of exertion be your guide.
In general, a low to moderate intensity workout will leave you feeling energized. A high intensity workout, on the other hand, delivers an ass-kicking.
If you’re sick, it makes sense to avoid the ass-kicking.
Let’s take a look at why.
How exercise affects the immune system
Exercise may play a role in both our innate and our adaptive immune response.
- After one prolonged vigorous exercise session we’re more susceptible to infection. For example, running a marathon may temporarily depress the adaptive immune system for up to 72 hours. This is why so many endurance athletes get sick right after races.
- However, one brief vigorous exercise session doesn’t cause the same immune-suppressing effect. Further, just one moderate intensity exercise session can actually boost immunity in healthy folks.
- Interestingly, chronic resistance training seems to stimulate innate (but not adaptive) immunity. While chronic moderate exercise seems to strengthen the adaptive immune system.
In the end, here’s the pattern:
- Consistent, moderate exercise and resistance training can strengthen the immune system over time. So, by all means, train hard while you’re healthy.
- But single high intensity or long duration exercise sessions can interfere with immune function. So take it easy when you’re feeling sick.
Exercise, stress, and immune function
A group of scientists gathering data on exercise habits and influenza found:
- People who never exercised got sick pretty often.
- People who exercised between once a month and three times a week did the best.
- People who exercised more than four times a week got sick most often.
Enter the J-shaped curve theory.
In simple terms, being sedentary or exercising too much can lower immunity, while something in the middle can improve immunity.
The role of stress
Exercise isn’t the only factor that affects the immune system. Stress plays a big role too.
Let’s take a look at the different stressors a person might face on any given day.
- Physical stress: exercise, sports, physical labor, infection, etc.
- Psychological stress: relationships, career, financial, etc.
- Environmental stress: hot, cold, dark, light, pollution, altitude, etc.
- Lifestyle stress: drugs, diet, hygiene, etc.
Stress triggers an entire cascade of hormonal shifts that can result in chronic immune changes.
- Acute stress (minutes to hours) can be beneficial to immune health.
- Chronic stress (days to years) can be a big problem.
So, if you’re angry, worried, or scared each day for weeks, months, or even years at a time, your immunity is being compromised. And you’re more ly to get sick.
Sickness and stress
It’s pretty obvious that if you’re actually sick and fighting an infection, your immune system will already be stressed.
And if you add the stress of prolonged vigorous exercise, you might, quite simply, overload yourself. That will make you sicker.
Plus, your history of infections can influence how the immune system responds during exercise. This can include everything from the common herpes simplex virus, varicella zoster, and cytomegalovirus, to hepatitis and HIV.
A healthy body might adapt to all that. But a body that’s fighting an infection is not a healthy body.
Overtraining and infection
What’s more, sudden increases in exercise volume and/or intensity may also create new stress, potentially allowing a new virus or bacteria to take hold, again kicking off a sickness.
Consider the 1987 Los Angeles Marathon, where one seven marathon runners who ran became sick within a week following the race. And those training more than 60 miles per week before the race doubled their odds for sickness compared to those training less than 20 miles per week.
This seems to work the opposite way as well. Chronic infections may actually be a sign of overtraining.
Learning from cancer & HIV
Exercise therapy is often recommended for patients with cancer in part because of how it modulates the immune system. Exercise seems to increase NK cell activity and lymphocyte proliferation. In other words, it looks exercise can be helpful.
Exercise interventions in those with HIV seem to help prevent muscle wasting, enhance cardiovascular health, and improve mood. We’re not sure how this works, though it may help to increase CD4+ cells.
Other factors affecting immunity
Besides stress, there are a host of other factors that can affect our immunity, and these can interact with exercise, either offering greater protection or making us more ly to get sick.
We’ve already touched on some of these. Here are a few more.
Our innate immune response can break down as we get older. But here’s the good news: staying physically active and eating a nutritious diet can offset many of these changes.
Menstrual phase and oral contraceptive use may influence how the immune system responds to exercise. Estrogens generally enhance immunity while androgens can suppress it. (Again, this may explain why women tend to do better with colds than men.)
Poor quality sleep and/or prolonged sleep deprivation jeopardizes immune function.
Exercising in a hot or cold environment doesn’t appear to be that much more stressful than exercising in a climate controlled environment.
For example, exercising in a slightly cool environment might boost the immune system. But full-fledged hypothermia may suppress immune function. While using a sauna or hot bath may stimulate better immunity in those with compromised immune function.
Exposure to higher altitudes has a limited influence on immunity.
It’s unclear exactly how obese folks respond to exercise in terms of immunity. Changes in insulin sensitivity and inflammation at rest may blunt or exaggerate their immune response to exercise.
There’s evidence that immune alterations affect mood and inflammation. Clinical depression is two to threefold higher among patients with diseases that have elevated inflammatory activity.
(Note: moderate exercise appears to act as an anti-inflammatory in those with inflammatory conditions).
There is a theory that IL-6 (a compound released after prolonged intensive exercise) may be produced in abnormal ways in some people, leading to fatigue, flu- symptoms, and depressed mood.
The more “trained” you are, the better your body tends to handle exercise. In other words, it’s not as much of a stressor.
Just in case you glossed over the previous sentence I’ll reiterate it: a higher level of fitness is protective as it may limit the stress response to exercise.
Textbook guidelines for exercising while sick
- Day 1 of illness:Only low intensity exercise with symptoms sore throat, coughing, runny nose, congested nose.No exercise at all when experiencing muscle/joint pain, headache, fever, malaise, diarrhea, vomiting.
- Day 2 of illness:If body temp >37.5-38 C, or increased coughing, diarrhea, vomiting, do not exercise.If no fever or malaise and no worsening of “above the neck” symptoms: light exercise (pulse
Exercising When Sick: A Good Move?
From the WebMD Archives
You have been so great about your new exercise routine, rarely missing a day since you started up again. Then all of a sudden you are waylaid by a cold or flu.
What should you do? Should you skip the treadmill or forsake that Pilates class for a late afternoon nap? Will it be hard to get started again if you skip a day or two?
The answer depends on what ails you, experts tell WebMD. For example, exercising with a cold may be OK, but if you've got a fever, hitting the gym is a definite no-no.
Fever is the limiting factor, says Lewis G. Maharam, MD, a New York City-based sports medicine expert. “The danger is exercising and raising your body temperature internally if you already have a fever, because that can make you even sicker,” he tells WebMD. If you have a fever greater than 101 degrees Fahrenheit, sit this one out.
Maharam's rule of thumb for exercising when sick? “Do what you can do, and if you can't do it, then don't,” he says. “Most people who are fit tend to feel worse if they stop their exercise, but if you have got a bad case of the flu and can't lift your head off the pillow, then chances are you won't want to go run around the block.”
Personal trainer and exercise physiotherapist Geralyn Coopersmith, senior manager of the Equinox Fitness Training Institute in New York, has this to add: “The general rule is that if it is just a little sniffle and you take some medications and don't feel so sick, it's OK to work out. But if you have any bronchial tightness, it's not advisable to be working out.”
You really need to know your limits, she says. “If you are feeling kind of bad, you may want to consider a walk instead of a run.
Take the intensity down or do a regenerative activity yoga or Pilates because if you don't feel great, it may not be the best day to do your sprints,” says Coopersmith, the author of Fit and Female: The Perfect Fitness and Nutrition Game Plan for Your Unique Body Type.
“A neck check is a way to determine your level of activity during a respiratory illness,” adds Neil Schachter, MD, medical director of respiratory care at Mount Sinai Medical Center in New York.
“If your symptoms are above the neck, including a sore throat, nasal congestion, sneezing, and tearing eyes, then it's OK to exercise,” he says.
“If your symptoms are below the neck, such as coughing, body aches, fever, and fatigue, then it's time to hang up the running shoes until these symptoms subside.”
An uncomplicated cold in an adult should be totally gone in about seven days, says Schachter, the author of The Good Doctor's Guide to Colds and Flu.
A flu that develops complications such as bronchitis or sinusitis can last two weeks, he says. “The symptoms of cough and congestion can linger for weeks if not treated.” In general, the flu, even if uncomplicated, can make you feel pretty rotten for 10 days to two weeks.
The best way to avoid the problem is not to get sick in the first place.
Exercise in general can help boost your body's natural defenses against illness and infection, Schachter says.
“Thirty minutes of regular exercise three to four times a week has been shown to raise immunity by raising levels of T cells, which are one of the body's first defenses against infection.
However, intense 90-minute training sessions those done by elite athletes can actually lower immunity.”
It's one thing if you decide to exercise when sick, but how do you keep from spreading it to others in the gym? And what about you if they are the ones exercising with a cold?
“Be careful that you are not blowing your nose constantly. And you should be using a towel and putting it down on every surface you touch and wiping it off when you are done,” says Equinox's Coopersmith.
“The value of hand washing cannot be overstated,” Schachter says. “I recommend washing hands before and after using the restroom, before meals, after using public transportation, and after returning home from school or work.”
Also carry alcohol-based hand sanitizer gel in your gym bag to use when you realize that you have come into contact with someone who is sneezing or coughing.
SOURCES:Lewis G. Maharam, MD, sports medicine expert.
Geralyn Coopersmith, MA, CSCS, personal trainer; exercise physiotherapist; senior manager, The Equinox Fitness Training Institute, New York; author, Fit and Female: The Perfect Fitness and Nutrition Game Plan for Your Unique Body Type. Neil Schachter, MD, medical director of respiratory care, Mount Sinai Medical Center, New York; author, The Good Doctor's Guide to Colds and Flu.
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