Hello all, this week I’m writing to you for the first time in four days not confined to bed rest. After a rough bout with the flu that rolled straight into strep throat, our house has become a bit of a revolving door for illness. It seems the flu and strep made their way through last week and never fully left. As I sit here now, I realize I haven’t run since 12/6 and likely won’t for another three to four days. That reality made this week’s newsletter an easy choice: getting sick and how to handle your running when illness strikes. It’s a topic athletes ask about constantly about.  LIke how to proceed, when to rest, and how to manage the mental side of missing training, especially when it happens at an inopportune time. For me, this falls during base season ahead of my next marathon, so I’ll be just fine, but there’s still a lot to unpack here. Let’s dive in.

 

-Nick K

So you get sick and know you probably need to take time off but you’re worried about how that time away will impact your training. Instead, you try to squeeze in a few extra runs or get one last workout done before resting, hoping your body will recover while the training momentum keeps rolling. This scenario is almost always destined to fail. Even if you “get away with it” in the moment, it will catch up to you and it’s rarely worth the cost. Beyond the physical stress, there’s a real mindset issue that shows up when you ask your body to perform workouts it simply isn’t ready to handle.

 

There’s an important difference between training with normal fatigue and training while sick. Fatigued legs and general training stress are adaptations we intentionally build into a plan to develop fitness. Illness is different. When you’re sick, you’re often starting a run with an elevated heart rate, poorer hydration, and fewer physiological resources available to support the work. What happens next is predictable: the workout feels much harder than expected, paces are difficult to hit, and the session doesn’t go as planned. You still end up needing time off afterward, but now you’re also questioning your fitness because "that shouldn’t have felt so hard.”

 

As runners, we tend to struggle with giving ourselves grace. When illness pops up, the fear is that time off will erase all the progress we’ve made. In reality, and this does depend on the severity of the illness, forcing training while sick often delays recovery and introduces unnecessary doubt into your training. You’re evaluating your fitness based on workouts done without all of your resources available. Be careful pushing through illness in the name of toughness; protecting your confidence is part of smart training, and sometimes the best way to do that is stepping back so you can come back healthy and ready to train again.

 

-Nick K Baltimore, MD

So how do you alter your training when you’re sick? When is the right time to pull back, and when, if ever, is it okay to keep running? These are big questions and some of the most common ones coaches get as athletes navigate illness. Runners often worry about taking too much time off, while simultaneously worrying about not taking enough.

 

One guideline you’ll hear frequently is the above-the-neck rule. If your symptoms are limited to above the neck, such as a runny nose or mild congestion, and you do not have a fever, it may be okay to keep running. That said, your body is still not operating at 100%, so intensity should be adjusted. Easy running is generally fine, but workouts and hard efforts should be scaled back or skipped. Think maintenance, not progression.

 

When symptoms move below the neck, chest congestion, a deep cough, body aches, or significant fatigue, it’s best to skip both workouts and easy runs and allow your body to rest. The same applies if you have a fever. If you are on antibiotics, extra caution is warranted: some medications can increase the risk of tendon injury or cause gastrointestinal distress, especially when paired with hard running or longer efforts.

 

It’s also important to note that frequent or prolonged illness can sometimes be a sign of overreaching or under-recovering. If you feel like you’re constantly getting sick or can’t fully shake an illness, your body may be asking for a bigger pullback so it can reset and recover enough to support training again.

 

Most importantly, listen to your body. Runners are often very in tune with how they feel.  They notice when heart rate is elevated, when effort feels off, and when something isn’t quite right. Trust that awareness. When in doubt, err on the side of rest. No one has ever lost a race goal because they took an extra day to let their body get healthy.

 

-Nick K Baltimore, MD

What question do you want the Running Explained team to answer in next week's newsletter mailbag? You tell us! Is there another question you'd like us to answer in a future issue? Send us a note!

 

— JoJo

You asked we answered and today's question you want to know about is “How do I know if a workout was successful”!

 

It’s a fun question to explore because early in a runner’s journey, success is easy to define. You do the workout, you finish it, and you walk away feeling accomplished. That alone is a win. But as you stack more training blocks and gain experience, success can start to feel harder to gauge. It’s not realistic, or useful, to assume that every workout or every new training block will automatically produce faster times. Fitness doesn’t work that way, largely because no workout is ever an apples-to-apples comparison. Internal factors (fatigue, stress, sleep) and external factors (weather, terrain, timing) are never exactly the same. Because of that, “faster” cannot be the only measure of success. Your criteria need to be more grounded.

 

Workouts are not single heroic moments; they are building blocks. Each one contributes to the larger goal of bringing fitness together when it matters most. Some phases are meant to push, others to absorb, and others to maintain. As a result, the definition of a successful workout should shift with the purpose of the training block. When you stop trying to “win” workouts by forcing impressive numbers and instead view them as deposits in the fitness bank—sessions you complete and walk away from in one piece—you start to redefine success in a much healthier way.

 

The real goal of training is sustainability. A successful workout isn’t the one that leaves you red-lining or completely empty every time; it’s the one you execute well, feel confident about, and recover from quickly enough to show up for the next session. If you can complete a workout, feel proud of the execution, and still be ready for your recovery run the next day and your next workout later in the week, that’s success. In fact, the less “heroic” a workout feels, the more likely it is doing exactly what it’s supposed to do for your long-term growth.

 

 

-Nick K Baltimore, MD

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