Feeling Flu-like Symptoms After Exercising?

It’s not uncommon to feel a bit worn out after a good workout, but feeling flu-like symptoms after exercise can be an unsettling experience. If you’re feeling sick after working out, it’s essential to understand the potential causes and what you can do to prevent these symptoms. Below, we’ll explore the causes of these symptoms, whether exercise can actually make you sick, and how you can avoid feeling unwell after working out.

Causes of Flu Symptoms After Exercise

Experiencing flu-like symptoms after exercise can be alarming, especially if you’re aiming to improve your health. However, there are several reasons why you might feel this way. Here are some of the main causes¹: 

1. Dehydration: Intense workouts cause sweat, leading to fluid loss. If you don’t replenish these fluids, dehydration can set in, causing symptoms similar to the flu, such as nausea after a workout, headaches, and muscle cramps.
2. Overexertion: Pushing your body too hard can lead to feeling flu-like symptoms after exercise. When you work out beyond your fitness level, your muscles and immune system can become temporarily compromised, which might make you feel sick or even experience chills after exercise.
3. Immune System Suppression: Prolonged or intense workouts can temporarily lower your immune system, which is why getting sick after working out can happen if you’re not careful. This makes it easier for viruses to take hold, especially if you’re exposed to germs in crowded gyms.
4. Poor Nutrition: Your body needs the right nutrients to repair itself after a workout. If you’re not eating enough or consuming unbalanced meals, you might feel sick after working out because your body is struggling to recover.
5. Toxin Release: Many people wonder, "can exercise release toxins and make you sick?" Exercise can indeed stimulate the release of toxins stored in body fat, which may lead to nausea after workout or other flu-like symptoms. While this is generally a positive effect, it can cause temporary discomfort.

Can Working Out Make You Sick?

Can working out make you sick? In some cases, yes, it can. "But why do I get sick after working out?" Let’s explore some common and uncommon reasons for feeling sick after working out: 

Why Do I Feel Nausea After A Workout?

Nausea after a workout is a common complaint, especially among those who push their limits. High-intensity or long-duration exercises require a lot of energy, and the body diverts blood away from the stomach to fuel muscles.² This can cause digestive discomfort, leading to nausea after a workout. Dehydration or eating too close to your workout can also make you feel nauseated. If you’re constantly getting sick after working out, consider hydrating more and allowing time between meals and exercise. 

I Feel Sleepy and Cold After Exercise

Do you often feel sleepy and cold after exercise? Intense workouts can trigger your nervous system to relax afterward, making you feel sleepy³. As your body starts to cool down, it can lead to feeling flu-like symptoms after exercise, including chills. This may be your body’s way of telling you that it needs rest to recover fully. Also, low blood sugar levels can leave you feeling cold and tired after an intense workout, especially if you haven’t eaten adequately.⁴ 

I Have Body Aches and Chills After Working Out

Body aches and chills after working out are also not unusual, especially after high-intensity sessions. When you push your body, small tears in muscle fibers occur, which is part of the process that leads to stronger muscles. However, these small tears can result in soreness and flu-like symptoms after exercise. If you experience chills after exercise along with body aches, your body might be experiencing mild inflammation, a natural part of the recovery process, which can make you feel sick.⁵ 

Tips to Reduce Flu Symptoms After Exercise

If you’re feeling flu-like symptoms after exercise, there are steps you can take to help prevent these discomforts in the future. Here are some tips to help you recover better and avoid feeling sick after working out: 

1. Hydrate Properly: Drink water before, during, and after your workout to prevent dehydration. Electrolytes are also helpful, especially if you’re doing high-intensity workouts or sweating a lot. Dehydration is a leading cause of nausea after a workout and can lead to flu-like symptoms after exercise.
2. Moderate Your Intensity: It’s great to challenge yourself, but be cautious about overexertion, which can lead to feeling flu-like symptoms after exercise. If you’re asking yourself, "Can you get sick from working out too hard?", the answer is yes. Pay attention to your body’s signals and gradually increase the intensity of your workouts.
3. Eat Balanced Meals: Eating a balanced meal with carbohydrates, protein, and healthy fats can help fuel your workouts and improve recovery. Poor nutrition can lead to getting sick after working out because your body lacks the resources needed to repair and rejuvenate itself.
4. Get Enough Rest: Your body needs time to recover after intense workouts. Overtraining without proper rest can suppress your immune system, making you more likely to experience fever after working out or other symptoms associated with illness.
5. Warm Up and Cool Down: Proper warm-ups and cool-downs can help regulate your body’s response to exercise, reducing the risk of body aches and chills after working out. Warming up prepares your body for intense activity, while cooling down gradually returns your heart rate and blood flow to normal levels, preventing drastic temperature drops.
6. Listen to Your Body: If you’re constantly feeling sick after working out or dealing with flu-like symptoms after exercise, take it as a sign that something may need to change. Rest and recovery are just as essential as the workouts themselves, especially if you’re experiencing unusual or severe symptoms.

Other Reasons You Might Experience Flu Symptoms

There are other reasons you might experience flu symptoms. In some cases, feeling flu-like symptoms after exercise may be related to factors beyond the workout itself. For example, allergies, recent illnesses, or underlying health issues could all contribute to getting sick after working out. Additionally, uncommon and common flu symptoms may sometimes overlap with post-exercise symptoms, such as mild fevers or body aches, which could make it challenging to pinpoint the cause.^{6, 7, 8} 

In conclusion, feeling flu-like symptoms after exercise is not uncommon and often occurs due to factors such as dehydration, overexertion, and improper nutrition. By following the tips outlined above, you can reduce the chances of feeling sick after working out and focus on building a healthier, stronger body. Remember, fitness is about listening to your body and balancing challenges with self-care. 

References

1. Peake JM, Neubauer O, Walsh NP, Simpson RJ. Recovery of the immune system after exercise. J Appl Physiol (1985). 2017;122(5):1077-1087.
2. Wilson PB. 'I think I'm gonna hurl': A Narrative Review of the Causes of Nausea and Vomiting in Sport. Sports (Basel). 2019;7(7):162.
3. Ament W, Verkerke GJ. Exercise and fatigue. Sports Med. 2009;39(5):389-422.
4. Brun JF, Dumortier M, Fedou C, Mercier J. Exercise hypoglycemia in nondiabetic subjects. Diabetes Metab. 2001;27(2 Pt 1):92-106.
5. Mizumura K, Taguchi T. Delayed onset muscle soreness: Involvement of neurotrophic factors. J Physiol Sci. 2016;66(1):43-52.
6. Nowacka-Chmielewska M, Grabowska K, Grabowski M, Meybohm P, Burek M, Małecki A. Running from Stress: Neurobiological Mechanisms of Exercise-Induced Stress Resilience. Int J Mol Sci. 2022;23(21):13348.
7. Clark A, Mach N. Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes. J Int Soc Sports Nutr. 2016;13:43.
8. Murphy EA, Davis JM, Carmichael MD, Gangemi JD, Ghaffar A, Mayer EP. Exercise stress increases susceptibility to influenza infection. Brain Behav Immun. 2008;22(8):1152-1155.