The Real Cost of Getting Sick
For endurance athletes, staying healthy while training is not about comfort. It is about protecting months of accumulated fitness.
Imagine that for every day you were sick, you had to dig into your savings and pay your employer two and a half days of income. Five days off would cost you 13 days’ income. A week off would cost you 18 days. Two weeks off would cost you 35 days.
If sick days cost you money, would that change how you interact with people? How much more cautious would you be about getting sick?
For endurance athletes, the math is real. When you stop training, a detraining process begins that induces a relatively rapid loss of the adaptations you worked so hard to build. The number of mitochondria in your muscles, which substantially determines your endurance capacity, can decline fast. Research suggests that half the mitochondrial increase from five weeks of training can be lost in a single week of detraining.
So for every unplanned rest day, you lose roughly two and a half days of mitochondria. That is the exchange rate. And it explains why illness prevention is not a soft skill for endurance athletes. It is a training discipline.
Why Athletes Get Sick: The Jenga Problem
Most athletes, when they get sick during a training block, blame the training. Too much volume. Too much intensity. They assume they overtrained their way into illness.
Sometimes that is true. But more often, it is not the whole picture.
Think of your immune system like a game of Jenga. Every stressor in your life is a block being removed from the tower. Training is one block. Work deadlines are another. Poor sleep is another. A cross-country flight, a fight with your partner, tax season, a toddler who brought something home from daycare—each one is a block.
At some point, the tower falls. When it does, which block was responsible? The last one you pulled? Not really. The position of every block contributed to the instability. The last block was just the last straw.
This is the single-factor fallacy applied to athlete health. We blame training because it is the most visible stressor, but susceptibility to infection is influenced by the cumulative load of everything in your life. Your body does not distinguish between “good” stress and “bad” stress. A hard interval session and a terrible night of sleep register the same way to your immune system: as demand.
This means that even a well-designed, well-periodized training plan can be the block that topples the tower if it coincides with a job change, a move, a family crisis, or any other spike in baseline life stress. The training was not too much in isolation. It was too much in context.
Understanding this changes how you approach illness prevention. You cannot just manage your training load. You have to manage your total stress load—and that means looking at everything.
Functional Mysophobia: A Framework for Staying Healthy
I spent the first four years of my skimo training in an up-and-down battle with illness. I would build up two or three months of training and start feeling really fit. Then I would get sick and spend two or three weeks on the couch, losing up to two months of fitness. Once recovered, I had to start the slow, tedious climb back up. The cycle repeated over and over.
In January 2018, I resolved to be smarter about it. If my friends and family thought I was crazy, so be it. I was sick and tired of watching months of hard work disappear. I decided that I would approach illness avoidance like someone irrationally afraid of germs.
I called it functional mysophobia: an intentional, systematic avoidance of illness that mimics the behavior of someone with a pathological fear of contamination—except it is entirely rational when your livelihood is measured in mitochondria.
And it worked. I did not have a single unplanned rest day for 425 consecutive days. My training volumes and intensities reached record levels. My race results were the best of my career. Acting like a crazy person for a year was a key component.
The framework has four parts, borrowed from risk management: probability, consequence, exposure, and vulnerability.
- Probability. What is the chance you will get sick, given your life and lifestyle?
- Consequence. What happens if you do? What do you lose?
- Exposure. How can you decrease the presence of threats in your environment?
- Vulnerability. How can you increase your resistance to those threats?
Your probability and consequence are personal and easy to figure out. With school-age kids and intermittent life stress, I was dealing with a probability of “near certainty” and a consequence of “big-time suckage.” What I could control was exposure and vulnerability. Here is how.
Decreasing Your Exposure to Germs
Exposure management comes down to two key areas: being wary of airflow, and avoiding communal control surfaces.
Airflow
A single cough can expel thousands of infected droplets at 50 miles per hour. A sneeze launches even more at 200 mph. The smaller, lighter particles can stay airborne almost indefinitely, carried by the room’s airflow. Think of air as water, and position yourself accordingly.
Stay upwind from people. Wind carries their germs away from you, not toward you.
Mind the wake. When passing someone in a hallway or on a trail who shows any sign of illness, inhale just before you reach them and exhale as late as possible after passing.
Avoid unhealthy people and their plumes of illness. The less time you spend around sick people, the lower your chance of inhaling something. In general, that means being cautious around obviously sick individuals, groups of children, the elderly, and sedentary people. The safest place to be is outside training. Unhealthy people do not exercise.
Avoid enclosures. Cars, gondolas, elevators, and small rooms can trap you inside someone else’s germ cloud. On a gondola, try to get your own car and open the windows to air it out from the previous occupants. Take the stairs when possible—unhealthy people prefer elevators.
Communal Control Surfaces
A communal control surface is anything that multiple people touch to operate something: door handles, light switches, remote controls, grocery carts, gas pumps, PIN pads, elevator buttons. Once you start thinking about these, you will be amazed at how casually everyone handles them.
The general rule: try not to touch them directly. When you must, use a barrier or a less contaminated part of your body.
Use your elbows. Try wiping your eye with your elbow. You cannot do it. That makes your elbow a perfect biomechanical barrier for things like light switches and push-doors. It is physically impossible for your elbow to reach your eyes or nose.
Use a knuckle. Especially useful for PIN pads and elevator buttons. Far fewer people use their knuckles, and knuckles are less likely to touch your face.
Use a barrier. A tissue, the end of your sleeve, or the hem of your shirt. When none of those work, contact the most unergonomic part of the surface—the spot no one else grabs. On a door handle, reach lower or wider than normal. At a magazine rack, take a copy from deep in the stack.
Carry your own pen. You never leave home without your keys, phone, and wallet. Add a pen. You will be surprised how often you need one, and how many other people’s fingers have touched the communal alternative.
Carry hand sanitizer. Same logic. Keys, wallet, phone, pen, hand sanitizer. Offer it to others—you are protecting them and yourself.
Never touch your eyes or nose directly. Runny nose? Sniff until you can find a tissue. Goopy eye? Use the inside of your collar. Never your bare hand.
Wash your hands obsessively. Build a habit of washing after anything that may have contaminated them. This is the single most effective hygiene behavior.
Reducing Your Vulnerability
Reducing exposure manages the threats outside of you. Reducing vulnerability strengthens the defenses inside you. The goal is to never spend your entire reserves on training, because your body needs some in reserve to fight off illness.
Manage Your Total Stress Load
This is where the Jenga problem becomes actionable. Ask yourself four questions:
What margin of safety do I need to deal with the unexpected and still stay healthy? At best, training is imprecise. It is foolish to try and calculate an exact margin. What works is to simply never go to your limits in training. Always aim to have one more hour or one more interval left in the tank. Do as much as necessary, not as much as possible.
With that margin of safety, do I have enough remaining bandwidth for the training I need? There is a reason many professional athletes live like monks. The fewer external stressors they manage, the more capacity they can devote to training. In contrast, the “go hard or go home” approach to cramming everything in is an exercise in playing with fire.
Can I decrease my baseline stress? Baseline stress is primarily work, people, and travel. Can you work less, or in a less demanding role? Can you spend less time with stressful people? Can you avoid non-essential travel? If a responsibility is not important, get rid of it. If it is important, accept it and work around it.
If not, can I accept the bandwidth I have and dial back my training? This is the hardest question for competitive athletes. But it is better to train at 80% of your desired load consistently than to train at 100% and get flattened by illness every three months. The athlete who trained consistently at a moderate load for twelve months will outperform the athlete who trained at maximum for three months and spent the rest recovering.
Sleep
Sleep is arguably the most powerful immune defense you have. The less you sleep, the more likely you are to catch a cold. When I made sleep a priority—at least eight hours per night, plus a 20-minute afternoon nap whenever possible—it was one of the biggest contributors to staying healthy.
If you have consecutive bad nights of sleep, change your training plan. Back off and have easy days until your sleep is restored. One crappy night usually does not make a difference. Two or three in a row is a signal to protect your reserves.
Nutrition
Make sure your diet is giving you the nutrients you need to support your training load and defend against illness. Eat enough to fuel the work required. Combining heavy training loads with calorie restriction is one of the fastest ways to suppress your immune system and get sick.
This is especially relevant for uphill athletes who are conscious of body weight. Watching your weight is fine, but not at the expense of fueling your training. If you are training hard and eating less than you need, you are choosing to get sick. It is just a matter of when.
Alcohol
Alcohol weakens the immune system for hours and days after ingestion and negatively impacts sleep. The brief gratification of drinking does not outweigh the increase in risk for an athlete in a serious training block.
Monitoring the Signals
Keep an eye on the data your body is giving you. An elevated resting heart rate, reduced heart rate variability, or multiple nights of poor sleep in a row are all signals that your stress load is exceeding your capacity. When you see these signals, give yourself grace. A lighter training day now prevents a week on the couch later.
Playing Defense: When Symptoms Appear
No matter how diligent you are, you may still catch something. At the first sign of symptoms—either in yourself or in someone you live with—you need to change your approach immediately. The goal shifts from building fitness to protecting fitness.
Sleep and eat. If you have any symptoms, your body is fighting something. Sleeping and eating will support your defenses. This is not the time for restraint.
Train less. Adjust your training plan immediately. Back off and go into maintenance mode until the threat has passed. It is much easier to make up for lost training from an unplanned taper than from a full-blown illness.
Avoid intensity. Postpone any intensity sessions until you are fully recovered. Adding hard efforts onto a struggling immune system will make things worse. Keep any training you do at low intensity.
Avoid fasted sessions. Glycogen depletion is an important tool in aerobic development, but it also compromises immunity. Do not combine depleted training with any symptoms—yours or a family member’s.
Mind the trend. As you sleep more, eat more, and train less, are your symptoms improving? If so, continue cautiously. If not, back off even more. The faster you respond, the shorter the illness tends to be.
Welcome to La-La Land
I started this approach in January 2018. After 425 days of uninterrupted training, I was fitter and faster than I had ever been. I trained at record volumes and intensities. My race results were the best of my career.
Acting like a crazy person for a year was a key component.
Your friends and family will notice. They will comment on the hand sanitizer, the elbow light-switch technique, the refusal to grab the door handle. When they voice concerns about your newfound mysophobia, ask them:
“If you had to pay me $300 for every day that I got sick, would you still think I’m crazy?”
For endurance athletes, the cost of illness is real and measurable. The defense against it is not complicated. It requires attention, consistency, and the willingness to look a little crazy.
You already have those qualities. You are an endurance athlete. Apply them here.