Should You Exercise or Rest When You’re Sick?

It’s tempting to stick to your workout routine no matter what, but when you’re under the weather, that decision isn’t always straightforward. Whether you're battling sniffles or something more serious, understanding how illness affects your body can help you decide if a sweat session is safe or if you should hit pause and rest.

The "Neck Check": A Simple Rule of Thumb

If you’re unsure whether to work out when sick, many health experts suggest a basic rule known as the "neck check." Here’s how it breaks down:

• Above the neck (like a runny nose, sneezing, or mild sore throat): It’s generally OK to exercise if you feel up to it.

• Below the neck (like chest congestion, fever, vomiting, or body aches): It's best to rest.

This guideline, rooted in a 1996 study, remains a helpful, if informal, way to assess your symptoms. But it’s not a green light for every type of movement. The key is to listen to your body and adjust your intensity accordingly.

When You’re Just a Bit Under the Weather

If your symptoms are mild and energy levels are stable, sticking to light or moderate movement may actually be beneficial. Gentle exercise like walking, yoga, or low-intensity cycling can help increase circulation and ease mild congestion.

However, even with mild colds:

• Avoid intense cardio or strength training, which can tax your immune system.

• Shorten your workout to avoid overexertion.

• Stay hydrated, as your body is using more fluids to fight off illness.

Why You Should Always Skip a Workout With a Fever

When a fever hits, there’s no debate exercise is off-limits. A fever raises your core body temperature, and adding a workout to that mix can lead to dangerous overheating. Plus, research shows that exercising with a fever can significantly worsen illness and even increase the risk of complications.

According to the Centers for Disease Control and Prevention (CDC), fever is also one of the primary signs that you’re contagious. So skipping the gym protects others as well.

Key reasons to avoid exercise with a fever:

• Higher risk of dehydration

• Decreased muscle strength and endurance

• Elevated risk of spreading illness

Coughing? It Depends on the Type

Coughs can be tricky. If you’re dealing with a dry, occasional cough and you feel fine otherwise, light movement might be okay. But a productive or frequent cough is a sign to rest.

Consider this scale:

• Mild, dry cough: Light activity may be okay.

• Moderate, persistent cough: Stick to very gentle movement, if any.

• Wet, heavy, or painful cough: Skip the gym entirely.

Why? Your respiratory system is already working harder. Adding cardio or strength training increases your body’s oxygen demands something that's hard to meet when you're already short of breath.

Runny Nose or Congestion? Proceed With Caution

Congestion and runny noses are typically considered “above the neck” symptoms, meaning you may be fine to work out especially if it helps you feel better mentally. Still, if your nose is so stuffy it’s impacting your breathing, dial back the intensity or opt for a rest day.

A 2017 study published in Frontiers in Physiology found that moderate exercise doesn’t worsen cold symptoms and may actually shorten the duration of illness. But the key word here is moderate.

Athletes and High Performers Aren’t Immune

If you train regularly or consider yourself in top physical shape, you might think you’re exempt from sick-day guidelines. Not so fast. Research shows that:

• Strenuous exercise when sick can increase injury risk

• Even trained athletes experience decreased performance and recovery if they push through illness

• The immune system can be suppressed for up to 72 hours after high-intensity training leaving you more vulnerable to complications

Long story short: even pros need to rest when sick.

When to See Your Provider

Always check with your doctor if you:

• Have chronic respiratory or heart conditions (like asthma, COPD, or cardiovascular disease)

• Develop worsening symptoms or trouble breathing

• Are unsure whether your illness is contagious or serious

Sometimes, skipping a workout for a day or two can get you back on track faster than pushing through and risking setbacks.

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