Cyclists can power through headwinds, hill repeats and frozen fingers – but what about a head cold? Even the fittest riders get ill. Here’s what really happens when athletes get sick, and how to recover without derailing your training.
Even the fittest athletes get sick, especially when heavy training, stress and poor sleep stack up. The real question isn’t whether illness happens, but how you handle it without turning a short setback into a long one.
You can handle the headwinds, training rides in darkness and the frozen fingers. But the one thing that derails winter training most often is just a tiny virus you caught from a random doorknob.
Do athletes get sick? Yep, they do.
The difference between a minor setback and a ruined season isn't your VO2 max – it's your plan to prevent illness, recover when you do get sick, and return to your training.
Fitness isn’t a force field that keeps you from catching germs. Athletes are human, and unfortunately, humans do get sick, especially during cold-and-flu season.
However, a lot of hard-working athletes are tuned in to changes in their bodies and may notice symptoms developing more quickly than others do. They’re used to keeping a close watch on their fatigue, resting heart rate and sleep quality, which are key indicators of when an illness is coming on.
Getting sick isn’t a failure and it doesn’t mean the end of your season, though.
The mistake is pretending it didn’t happen. Training when you’re sick can set you up for slower recovery, injury and even worse illness.
This article offers general lifestyle and training guidance for cold-and-flu season, but not medical advice. If you have severe symptoms such as a fever, chest pain or symptoms that keep getting worse, seek care from a medical professional.
Studies show that moderate exercise can boost your immune system and help you stay healthier. A Finnish Institute of Occupational Health study found that people who commute to work by bike take fewer sick days than their car-commuting coworkers.
On the other hand, there is also evidence that heavy training load hampers your immune system. Think of it this way:
After a very heavy training session, your body experiences inflammation and an increase in stress hormones. It’s focused on recovery and repair, rather than on keeping germs at bay. This can lead to a temporary disruption of the immune system, which can last several hours to several days, in which you can be a little more susceptible to getting sick.
Some research, including a paper in Exercise Immunology Review, suggests very heavy, prolonged training blocks – especially in elite athletes – may increase susceptibility to minor infections like upper respiratory symptoms, compared with moderate exercise.
In this Women’sHealth article by Olivia Luppino, Dr. Marissa McCay, a sports medicine physician, says:
In some cases, that stuffy nose might not be a cold at all, but rather your body’s way of dealing with inflammation after a big event like a fondo or a marathon.
“The symptoms that people have after marathons, some of them may be infectious, but many of them are not,” says Dr. Sawalla Guseh, director of the Cardiovascular Performance Program at Massachusetts General Hospital in Boston, in the same Women’sHealth article by Luppino. “It's just your body's response to the inflammation caused by a massive stress.”
The science isn’t perfect, though, because fitness and health are affected by all kinds of factors, like sleep quantity and quality, travel, stress, nutrition and even the level of exposure to germs.
So when you stack a hard session with poor sleep or low fuel, you’re really running low on recovery. This leaves an open window for germs to sneak in and wreak havoc.
Not surprisingly, then, one symptom of overtraining is frequent colds, because hard training and immune issues are so closely linked.
As a mom, it’s hard to say if my last bout of the flu was from overtraining or something my kids brought home from school. Thankfully, these types of illnesses are usually minor and recovery is quick.
“Just rest,” my cycling friends told me when I complained of a headache, chills and body aches.
So I dutifully sat in my bed, with a heating pad for the chills, Tylenol for the body aches and darkness for the headache, with my kids regularly delivering ginger ale and hot tea.
“Don’t feel guilty,” they told me. “You deserve to rest so you can get better.”
Matti Weith is right – many of us just see illness as another challenge to overcome with grit and determination. But cycling when we’re sick isn’t usually a good idea.
How sick is too sick to ride? The mainstream rule of thumb says never exercise with a fever, and only when symptoms are above the neck. Let’s take a closer look.
🟢 Green Light: You get a green light for gentle exercise (easy rides, stretching) as long as you have mild, above the neck symptoms and no fever. If you’ve got a stuffy nose, hard rides are out of the question, but you could do short easy spins, easy-paced walks or mobility work.
🟡 Yellow Light: If your symptoms are progressing, if fatigue is rising, you’ll want to take this seriously. Consider complete rest or very short, very easy movement so you don’t end up making yourself sicker.
🔴 Red Light: If you’ve got a fever, chest symptoms, body aches, or GI issues, you’ll absolutely want to rest and even consider medical advice.
Even though cycling is low impact, the level of intensity still counts. If you’re sick, you’ll probably want to avoid hard intervals, group rides, and crowded gyms for as long as you are symptomatic and for at least 24 hours after being fever-free.
If you are going to ride when you don’t feel your best, keep it boring. No spicy intervals or hard rides, keep it light and focused on proper recovery.
The ROUVY indoor cycling app makes light recovery rides simple and stress-free. No traffic, no bad weather, no pressure. Spin gently, rebuild gradually and return to full strength on your terms.
Your cheapest performance enhancer – and likely your favourite – is getting extra sleep. It’s probably the number one most practical thing you can do to get better, faster and prevent illness in the first place.
If you are sick, fuel like you’re training, not like you’re dieting. Energy deficits and heavy training don’t play well together and set you up to get sick. Eat and drink to support your recovery, whether that’s from a cold, or hard training.
Don’t touch germy stuff. Open public doors with a tissue, avoid doorknobs and other hard surfaces that other people have touched, especially in that post-workout window that makes you a bit more susceptible.
Avoid crowded spaces to prevent particle transmission and wear a mask if you must be somewhere with a lot of people. And don’t forget the sanitizer!
If you ride indoors, take a few simple precautions like wiping down your tablet or keyboard, phone, and water bottle. Use good ventilation in the pain cave and don’t share towels.
A sauna or cold shower combo is a nice recovery habit to keep, and it may give you a little bit of an immune boost too.
It can be tempting to jump right back in where you started, but that’s not necessarily the best way.
There’s no reason to ride when you’re sick; it’s too risky and there aren’t really any benefits, GCN’s Conor Dunne says in this video. Instead, wait until your resting heart rate is back to normal. Then you can rewind your training program by a week or two, and gently start back in.
In an interview, Neal Henderson, the founder and president of APEX Coaching, said he has his athletes return to training within a week at about 50 percent of their normal training load to prevent injury or a return of symptoms.
Your first day back should be so easy it feels silly. Start at around 50 percent of normal duration and keep the intensity easy.
If symptoms stay away, you can start building back up. If symptoms come back, that means you started up too soon.
| Phase | Training Load | Focus | What It Should Feel Like |
|---|---|---|---|
| Sick Phase | 0% | Full rest and recovery | Prioritize sleep, hydration and nutrition |
| First Days Back | ~50% of normal duration and intensity | Easy spins or light movement only | So easy it feels almost too gentle |
| Gradual Build | 60-75% of normal load | Reintroduce structure slowly | Comfortable effort, no lingering symptoms |
| Full Return | 100% | Resume normal training plan | Back to baseline energy and resting heart rate |
| Training Load | |
|---|---|
| Sick Phase | 0% |
| First Days Back | ~50% of normal duration and intensity |
| Gradual Build | 60-75% of normal load |
| Full Return | 100% |
| Focus | |
|---|---|
| Sick Phase | Full rest and recovery |
| First Days Back | Easy spins or light movement only |
| Gradual Build | Reintroduce structure slowly |
| Full Return | Resume normal training plan |
| What It Should Feel Like | |
|---|---|
| Sick Phase | Prioritize sleep, hydration and nutrition |
| First Days Back | So easy it feels almost too gentle |
| Gradual Build | Comfortable effort, no lingering symptoms |
| Full Return | Back to baseline energy and resting heart rate |
Important: If symptoms return at any stage, reduce load again and give your body more time to recover.
We’re often too driven to keep up with our workouts, no matter what else is happening in our lives. But when you’re feeling under the weather, you’ll want to avoid some of these common mistakes:
Trying to sweat it out. This is a myth. Sweating it out won’t bring you back any faster. You have to rest it out.
Turning an “easy spin” into tempo because you feel guilty. You deserve to rest when you’re sick! If you’re off the bike for 2 weeks and, yes, you may lose 5 to 10 percent of your fitness – but rest assured that it will come back when you’re healthy.
Jumping back to intervals the moment you feel 80 percent. Jumping in too hard too soon is a recipe for getting sicker or not recovering. If you jump in too hard, you’re at risk for injury, too.
Whether it’s a heavy training block or a “gift” from your kids’ classroom, illness is going to happen. Don’t let the guilt of a missed workout weigh more than the symptoms themselves.
Lean into the rest, enjoy that extra cup of tea, and trust your training. You’ve put in the work; now, give your body the space to keep it. We’re athletes, but we’re also human. And sometimes, the most “pro” thing you can do is just stay in bed.
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