Exercise has so many health benefits that the American College of Sports Medicine wants to make it the standard of care. Plus, unlike medications, exercise has only positive side effects. It can even improve your immune health system response to viruses and other pathogens if you don’t overdo it.
Studies suggest that consistent, moderate-intensity exercise modestly improves immune health and defenses against viral infections. However, there is a window period after a hard workout where you may be more susceptible to infection due to the stress of exercise. Some research suggests that this window period is accompanied by a reduction in the amino acid tryptophan since exhaustive workouts increase the breakdown of tryptophan.
Regardless of why it’s important to have ways to keep your immunity up if you train frequently or intensely. Let’s look at some ways, backed by science, to support immune health when you work out.
Probiotics & Immune Health
Some research suggests that supplementing with probiotics is beneficial for preventing viral infections in athletes and people who train hard. Since the window period where immunity is suppressed after exercise is associated with decreased tryptophan, probiotics may help by boosting tryptophan.
Does the idea of supplementing with probiotics for immune health hold up to science? One study in athletes found that taking a probiotic supplement helped preserve tryptophan after a workout. It also modestly reduced the incidence of upper respiratory tract infections in athletes who did high-volume workouts.
Therefore, probiotics may modestly protect against upper respiratory infections by preventing the drop in tryptophan that people experience after aerobic exercise. Probiotics may also reduce the incidence of upper respiratory infections by interacting directly with the gut immune system and the gut microbiome.
Consume Carbohydrates after a Workout
Since there’s a window period after a workout where immunity wanes, eating a carbohydrate-rich snack makes a difference. How? One reason immunity decreases after a workout is intense or long-duration exercise boosts the release of the stress hormone cortisol and cortisol suppresses immune function. Consuming 30 to 60 grams of carbohydrates every hour during an intense workout and eating a carbohydrate-rich snack right after a workout reduces cortisol and its suppressive effect on the immune system. So, don’t skip that after-workout snack! You need it to replenish energy stores and for immune health.
Branched-Chain Amino Acid Supplements
Some bodybuilders and athletes take branched-chain amino acid supplements to support muscle hypertrophy. These amino acids play a key role in activating muscle protein synthesis. They may also be good for immune health. Research shows intense exercise reduces glutamine, an amino acid that supplies immune cells with the energy they need to function. If you can replace that glutamine, it may boost immune function. Fortunately, branched-chain amino acids can be converted to glutamine to supply immune cells with this amino acid. Branched-chain amino acids may also reduce muscle damage and muscle soreness after a workout.
Consume Adequate Nutrition
Immune cells require sufficient energy and nutrients to optimize their function. Skimping on calories and nutrition before intense workouts make it harder for immune cells to optimize their function. During that window period after a workout when immunity wanes, cortisol is higher, and you need adequate carbohydrates to lower it. Otherwise, your immune system will be more sluggish and less responsive.
One study found that athletes who dieted more often to lose weight had a 2-fold higher risk of developing an illness over a 3-month period. Intense exercise and excessive calorie restriction can also slow resting metabolic rate and make it harder to lose weight. If you’re doing intense or long-duration workouts, focus on eating a nutrient-dense diet and ensuring your body gets adequate calories. Don’t try to lose too much weight too quickly. Focus on health and performance over weight loss.
Sleep, Rest, Recovery, and Immune Health
People tend to underestimate the importance of sleep for a healthy immune system. According to the Sleep Foundation, skimping on sleep reigns in the body’s natural immune response by blocking the release of cytokines that activate immune cells. Studies show that people who don’t get enough sleep also have less robust immune responses to vaccinations.
Other than the impact sleep has on cytokine release, sleep helps redistribute immune cells called T-cells into the lymphatic system where they’re more available to fight viruses and other foreign invaders. The most beneficial stage of sleep for immune health is slow-wave sleep. That’s why it’s important to ensure your body cycles through each stage of sleep at night so your body gets the full benefits that each stage offers.
Research suggests that 7 to 8 hours of sleep per night is optimal for most people, but if you do frequent, intense workouts, you may need slightly more. Keep a sleep diary and document how many hours of sleep you get each night and how you feel. If you don’t feel your best with 8 hours, try adding another 20 to 30 minutes to your sleep schedule. It’s too important for muscle recovery and for immune health not to optimize.
The Bottom Line
A bad cold or other upper respiratory infection can make it hard to exercise for a few days. Make sure you’re doing the obvious things like eating a nutritious diet and getting enough sleep. Don’t exercise too much and not give your body a chance to recover between sessions. Also, don’t skimp on your post-workout snacks either. Feed your body carbohydrates to reduce cortisol and help your immune system recovery. If you do long or intense workouts, you may benefit from probiotics or a branched-chain amino acid supplement. You can make a sports shake that includes branched-chain amino acids for recovery.
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