Posted On:
Friday, April 19, 2024
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How to Handle Training When You Get Sick

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You are Human

If it hasn’t already, sooner or later, it will happen to you.  You will get sick.  And it will impact your training.

Every human on the planet is susceptible to illness, and every human on the planet will get sick at some point in their lives.  For athletes, getting sick is a frustrating experience, to say the least.  But what exactly are the impacts of illness on training, and how should endurance athletes handle things when they do (inevitably) get sick?

Acknowledge & Accept That You’re Sick

The most important thing that athletes need to do when they are sick is to accept that they are, in fact, sick.  Yes, it’s true that sometimes allergy symptoms can mimic illness.  Unless you have severe allergies and it’s actively a season where the things you are allergic to are active, if symptoms linger, get worse, or spread over the course of a couple of days, you are probably actually sick with an illness.

Over the years, I have worked with so many athletes who denied that they were sick when they were actually sick, and it cost them - both in the short and in the long-term.  It’s really important to acknowledge and accept when you are sick.  Don’t be stubborn and think that you’re the only human on the planet who is not susceptible to contracting a bacterial infection or a virus.  It simply isn’t true.  If you aren’t feeling well, you’re not feeling well.  If you’re sick, you’re sick.  And this is very okay.  Perhaps also very frustrating.  But also very okay.

Prioritize Healing, Not Workouts

Once you acknowledge and accept that you are, in fact, human and that you are, in fact, not the only human in history not to be immune to all contagions, prioritize healing and getting well.  Acknowledging that you are sick also means that you need to acknowledge that your body needs all available resources to be able to fight off the illness in question.  This means temporarily prioritizing your workouts less than you may be used to.

As I have said countless times before: The body knows when it is under stress.  But it is absolutely terrible at distinguishing the source of that stress.  So whether stress is imposed on the body due to lack of sleep, a hard day at work, a fight with your spouse, the antics of a hormonal teenager, a workout, or illness, all the body knows is that it is under stress. 

Being sick is very stressful on the body, as being sick pulls the body out of homeostasis.  Homeostasis is the state of steady internal and chemical conditions maintained by living systems.  In other words, homeostasis is a state of balance among all of the body systems needed for the body to survive and function correctly.  Illness puts the body out of balance, and it takes a lot of resources for the body to bring it back into balance.

When the body is out of homeostasis (such as when you are sick), any additional stress imposed on it will be counterproductive and will slow healing times.  This means that completing workouts at the same duration, intensity, and effort levels that you are used to is counterproductive.  

Working out while sick often means that sickness is unnecessarily prolonged, as the body needs to divert the resources it would have used for healing to power the heart, lungs, muscles, and other body systems to complete the workout.  In most cases, working out while being sick is going to feel terrible.  At the very least, it won’t feel great.  And most importantly: You will probably not derive any positive training benefit from it.

So when you’re sick, prioritize healing by hydrating, getting extra sleep, and eating nutritious food as much as possible.  Your body needs all of these things more than it needs workouts when you are sick; all of these things will help support your body and give it what it needs to fight off whatever illness it is that you’re facing.

What if I’m Not “That” Sick?

It’s true: Not all illnesses are created equal.  While all illnesses do have at least some impact on the body, not all illnesses have the same amount of impact on the body.  Some illnesses are far more impactful than others.

Generally speaking, you can continue to do workouts if your symptoms are contained within your head.  Think: runny nose, ear aches, scratchy throat, etc.  (Basically, having the common cold.)  While you can continue to do workouts with symptoms like this, you should be modifying what you’re doing.  Decreasing duration, intensity, or both is a good idea.  Managing expectations is also important; just because it’s relatively safe to do workouts with symptoms like this doesn't mean that you’ll have the same level of performance that you’re used to when you are healthy.  A few things you can expect: You will be slower, your power outputs will be lower, fatigue will onset more quickly, and you will not see adaptations during this time.

When to Seek Out Guidance from a Medical Professional

Not all illnesses require a trip to the doctor, but some do.  If your symptoms continue to get worse or linger for more than a few days, it’s a good idea to go to the doctor, get a diagnosis, and get some guidance on what your current illness means for your training.

Don’t get frustrated with or ignore a medical professional if they advise that you take time off from workouts.  Even if they are telling you something that you don’t want to hear, they’re almost certainly telling you what is in your best interests.

How Athletes Should Handle Fevers, Stomach Bugs, and Respiratory Illnesses

There are certain times when ceasing workouts is truly the best course of action.  This is true if you have a fever, your symptoms spread away from your head and are in your chest, and/or you have a stomach bug/gastrointestinal illness.


Fevers are one of the hallmarks of the body being out of homeostasis.  And for adults, fevers are honestly pretty rare; an adult needs to be pretty sick for a fever to happen.  Fevers are an incredibly important part of the body’s immune system.  Most of the viruses and bacteria that cause infections and illness in humans thrive at our normal average body temperature: 98.6ºF.  In response to the bacterial or viral invaders, the body raises its temperature to make the environment inhospitable to viruses and bacteria and to kill them off.  

While fevers feel pretty awful, they are actually working for you, not against you.  As long as you have a fever, it’s very unwise to do workouts.  For fevers of 102.0º or less, I advise athletes to wait until they are fever-free for at least 24-48 hours to resume workouts.  If athletes have a fever higher than 102.0ºF, I recommend that they wait until they’ve been fever-free for at least 5-7 days before they resume workouts.  When I say “fever-free”, I mean that athletes should be fever-free without medication.  Medications such as acetaminophen or ibuprofen do lower fevers, but when we’re considering when to return to workouts, we are seeking signs that your body is returning to homeostasis.  The only way to truly know this is to see how your body is doing without fever-reducing medication.

Symptoms in Your Chest

If your symptoms are in your chest (think wet cough, productive cough, compromised breathing, tight/sore chest, etc.), then you no longer have head cold symptoms; it’s either progressed into something worse or it’s always actually been something worse.  At this point, the lungs are involved, which means that the lungs are not only compromised, but the heart is going to work harder because the lungs aren’t functioning optimally.  As a result, the heart needs to pump more frequently to transfer oxygen around the body.  Doing workouts when you have symptoms in your chest is definitely not advised due to the additional strain that workouts place on the cardio-respiratory system.

Stomach Bug/Gastrointestinal Illness

If you have a stomach bug or gastrointestinal illness (symptoms of vomiting, diarrhea, or both are indications of this), dehydration is a very real risk since you are losing fluids faster than you are able to consume them.  When you have symptoms such as these, workouts are not only unwise from a physiological standpoint, they’re impractical from a logistics standpoint.  A workout isn’t going to be able to be completed anything close to what it needs to be if you are having to throw up, make frequent trips to the restroom, and if you cannot hydrate sufficiently.

The Impact of Illness on Training

If you get sick, you will likely have to not only miss some workout sessions, but you will also need to scale back what you’re doing when you do resume doing workouts.

I’ve coached literally hundreds of athletes through having illnesses over my career as a coach.  I’ve learned that it is generally best to expect it to take twice as long as you were “out” to feel somewhat “normal” in your training again.  Some illnesses (such as influenza, COVID-19, pneumonia, bronchitis, Lyme Disease, mononucleosis, etc.) actually extend this timeline beyond double the length of the illness, but in my experience, recovery timelines are rarely - if ever - shorter than double the length of an athlete’s illness.

So if you are sick for a week, don’t get annoyed when it takes two weeks to feel more “normal” again.  If you have symptoms and/or are sick for three weeks, it will take at least six weeks to feel more like your “normal” again.  If you contract influenza, COVID-19, or pneumonia, it will likely be months (not weeks) before you feel “normal” in your exercise again.  Some illnesses (COVID-19 and Lyme Disease are just two of them) may cause an athlete to never feel the same as they did before they got sick. 

Getting sick is a form of unplanned detraining and, depending on the illness, can be a form of unplanned training cessation.  Detraining is the partial or complete loss of training-induced adaptations in response to a lower or insufficient training load.  Training cessation is a complete stop of all training-related activities.  Unplanned detraining or training cessation occurs when an athlete has something unexpected happen (such as illness, an injury, etc.) that causes them to have to take time off from training and/or reduce their training load.  (Conversely, planned detraining or training cessation happens when an athlete or a coach plans for a decrease in fitness or a stop in training-related activities; examples include recovery weeks, weeks off (such as during vacations), or Maintenance Phase.)

Unplanned detraining and/or training cessation means that during the time that you are sick and during the time that your body is recovering from being sick, you will not be making progress from where you were before you got sick.  You will only be recovering to get to a point where you can handle training at the volume and intensity that you could before you got sick.  Your actual abilities will diminish during this time, and you will be “behind” where you were right before you got sick.

Illness is a setback.  That’s the hard truth.  No amount of positive thinking or willpower will change that.

Once that “double time” window has passed, you will still be regressed fitness-wise behind where you were when you got sick, but since you’ll be recovered enough to handle “full” training, you can then start to make and expect forward progress and gains in your fitness.  In my experience, this truth is the hardest thing for athletes to wrap their minds around and accept.

The amount of patience that this process requires is very real.  That being said, trying to rush or expedite this timeline because you don’t like it, wish it was different, or think that you’re the exception isn’t going to serve you well.  Disregarding what it takes for the body to heal and rushing back into workouts prematurely is going to stress your body more, prolong your illness, and therefore extend your timelines even further and/or cost you more fitness-wise than if you manage your return to training with thoughtfulness and wisdom.

The Impact of Illness on Race Day Performance

If you get sick close to your A-Goal Race, you will likely need to adjust your expectations of the day, especially if you have a performance-based (time-based) goal.  Setbacks in training that occur within the final 8-12 weeks before race day will (not might) have an impact on how you perform on race day compared with how you would have performed if you didn’t get sick and have a disruption to your training.  This is because you don’t have the luxury of enough time to be sick, to recover from being sick, and to then make enough gains in your fitness to have the same level of performance that you would have been able to have if you had been healthy during your training cycle.  This is frustrating, and it’s also true.

Many of the athletes I’ve coached over the years have gone to the doctor when they’ve been sick and they’ve asked about whether or not they’ll be okay to do the race that they’re training for.  It’s not uncommon for a doctor or medical provider to say “You’ll be okay to race” or “You’ll be good to go for your race” to an athlete.

There’s something really important that athletes should keep in mind about this.  First and foremost, if you are an endurance athlete, you are very different from the general population because you are doing something (training for endurance events) that is literally extraordinary.  A lot of people exercise; very few people train.  So honestly, it’s not uncommon for medical providers to misunderstand what you actually mean when you say you’re training for a race.  When they tell you that you’ll be okay to race, what they think of as a race and what you think of as a race are very likely two different things.

Secondly, if a medical provider tells you “You’ll be okay to race” or “You’ll be good to go for your race,” they almost always mean this: You will be okay to do the race.  The statement “You’ll be okay to race” or “You will be good to go for your race” does not mean that you can or that you should expect the same performance you would have had if you didn’t get sick and if you didn’t have this interruption and set back in your training.  In other words, while you may be okay to do the race (as in complete) the race, you may or may not actually be recovered or fit enough to actually race the race.

All of this means that it’s really important to reframe and reset your expectations when it comes to race day after you’ve been sick during your training.  If you do not do this, you will end up disappointed and frustrated when race day comes and your race performance isn’t what you wanted or expected.

The Bottom Line

Since getting sick is an inevitable happening for all humans, it’s something that all athletes will face at least once during their training for their goals.  When the day comes that you are actually sick, it’s important to accept it, recognize what it actually means for your training, modify things appropriately, and manage your expectations in terms of both timelines and performance so you can recover and come out on the other side ready to resume training and to pursue your goals.


Coach Laura Henry

Laura Henry is a Syracuse, NY-based coach who is a USA Triathlon Level II Long Course and Level II Paratriathlon Certified Coach, USA Cycling Level 2 Certified Coach, VFS Certified Bike Fitter, and has successfully completed NASM's Certified Personal Trainer course. Coach Laura is passionate about helping athletes of all ability levels reach their goals and has coached many athletes to success.

She can be reached at

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