You know exercise builds muscles, strengthens bones, keeps your heart healthy and your mind sharp. But it also does something that you might not think much about: It helps keep your immune system — your internal defenses against infection — in tip-top shape.
If you take time for some physical exertion each day, it helps get your body ready to attack bacteria, viruses and toxins that can sneak in and make you sick.
But how much exercise is effective? Do too little or too much, and it won’t have the best effect on your immune system.
Clinical immunologist Leonard Calabrese, DO, answers common questions about how exercise can impact your immunity and how to use your workouts to shut out a world of would-be invaders.
Q: How does breaking a sweat boost immunity?
A: If you exercise moderately on a regular basis, it tunes up the immune system in many ways. It enhances your broad-based defenses against viral infections, such as those causing upper respiratory infections.
Working out regularly also reduces the risk of many chronic diseases such as cardiovascular, respiratory illnesses and metabolic diseases, such as type 2 diabetes.
Q: How much exercise do you need?
A: Fortunately, you don’t have to push yourself to the limit to rev up your immune system. In fact, your immune system needs less of a workout than you get with your average cardio routine.
Focus on getting 20-30 minutes of moderate exercise, five days a week, and your immune system will thank you.
Q: What types of exercise are most helpful?
A: Moderate exercises, including biking or walking briskly in your neighborhood, are good ways to get your blood flowing. Swimming is also a good option for non-weight-bearing exercise for your joints.
Also try mind-body exercises such as Tai-Chi, Qi Gong and yoga, which are all options that help keep your joints flexible. These exercises also reduce chronic stress, which in itself is a powerful immune booster. These exercises can also help alleviate osteoarthritis and fibromyalgia symptoms.
Q: Can too much exercise set your immune system back?
A: Yes, though, the level to which it can slow your system down is still up for debate.
Research shows that exercising for more than 1.5 hours without refueling your body or giving it enough time to recover suppresses your immune responses for up to a few days. During that time, your cortisol levels rise, your white blood cell count drops and you’re more likely to develop a respiratory infection.
This problem usually affects elite athletes, such as marathon runners, most.
On the flip side, staying sedentary also increases your risk of infection, inflammation and chronic disease.
Q: Can exercise make an illness worse?
A: Yes, it can. This is a complex issue, but I like to tell my patients to do a “neck check.” If your symptoms are mostly of a mild cold without fever or lower respiratory symptoms, such as a productive cough, wheezing or shortness of breath, mild exercise can actually reduce congestion and may make you feel better.
If your symptoms are primarily in your lungs or you have a significant fever its better to rest until things settle down. Regardless, good hydration is important.
If you run regularly, whether it’s an easy jog around the block to stay fit or an intense training regimen to prepare for a marathon, you need proper nutrition.
Here are some tips to help keep runners well-nourished and ready to win.
Foods for Runners and Joggers
A good diet can boost your physical health and help you meet your fitness goals. Make sure your meals emphasize the following basic components:
Fruit and vegetables for vitamins, minerals and antioxidants
Lean protein such as fish, poultry, beans, lentils and tofu
Healthy fats such as olive oil, avocado and nuts
Healthy carbohydrates such as rice, whole grain breads/pastas and oatmeal
Individuals may have different optimal balances, but in general, people who include running or jogging as part of their fitness regimen should get 60% to 70% of their calories from carbohydrates, with lean protein and healthy fats each accounting for 15% to 20% of their remaining calories.
Don’t skimp on carbohydrates
Although low carbohydrate diets are popular go-to’s for people wanting to lose weight, they’re not ideal for distance runners, who thrive on carbohydrates for endurance.
That is why very low carbohydrate diets, such as the ketogenic diet, plus running is not a good idea. Experts do not recommend keto to runners unless they have been told by their doctor that this a medically safe option for them and they are being monitored while in ketosis.
Distance runners need more carbs than people who aren’t training. Undereating carbohydrates can be hard on your body and affect your recovery after your run.
Here’s why: Running uses both glucose in the blood and your stores of glycogen. Glucose is the form of sugar that circulates in the bloodstream, and glycogen is the sugar stored in your liver and muscles that acts as the primary fuel for endurance exercise.
Eating plenty of carbs helps ensure that these energy stores are ready to support your training. When those stores get too low, runners are more likely to run out of energy and “burn out” or “hit a wall” while training.
Running Diet — Vitamins and Minerals
Running changes your body and your nutritional needs. Often when people start a running regimen, they are trying to lose weight or get in shape quickly, and they don’t realize they need to adjust their diet.
Especially in women runners, dietitians report seeing a tendency to overdo the running while not eating enough, and this can have an effect on health if they do not adequately replenish lost vitamins and minerals in their diet.
For women in particular, calcium and vitamin D are essential for bone health to avoid loss of bone mineral density and the risk of stress fractures.
For more vitamin D, include these foods in your meals:
Vitamin D-fortified dairy and almond, soy or rice based beverages
Eggs
Cereal fortified with vitamin D
Tuna
Salmon
For more calcium, try:
Yogurt and cheese
Tofu
Edamame
Almonds
Canned fish with bones (such as sardines)
Iron deficiency can affect women and even have an impact on their running performance. Menstruation puts people at higher risk of iron deficiency, and if iron isn’t replenished in the diet, decreases in hemoglobin can occur and bring on anemia. Hemoglobin is what carries oxygen throughout the body, including the muscles, so if there is a deficit, the muscles may feel the effect of insufficient oxygen during exercise.
Iron-rich foods include:
Poultry and other meat
Legumes, such as peas and beans
Dark, leafy green vegetables such as kale
Dried fruits and raisins
Iron-fortified breads and cereals
Dietitians recommend eating eating iron rich foods in combination with foods high in vitamin C, such as citrus, bell peppers or berries, since vitamin C helps increase the body’s absorption of iron.
What to Eat Before Running ― and When
The best time to eat a full meal is about two to three hours before you hit the road, track or trail. Have a good source of carbs paired with protein, making sure the meal focuses on a healthy carb source.
If it’s been more than three to four hours since you’ve eaten, a carbohydrate-rich snack a half-hour before running can ensure you have adequate glucose available before you head out. Directly before a run, it’s best to stick with easy-to-digest carbohydrates to avoid gastrointestinal [GI] distress such as cramping or diarrhea.
Try these:
Bananas
Applesauce
Crackers, pretzels or cereal
White bread
Potatoes
Glucose Boosters for Long Distance Runners
If you are training for a marathon or distance event and are going to be out for over an hour, you will want to bring some fuel with you. Energy drinks, gel tubes and other sources of quick blood-glucose boosters are available, but you can also use something as simple as fruit snacks.
Try practicing with these items as you train so you can pick the formulas that are best for you, and you can work on accessing and ingesting them smoothly without breaking stride.
What foods should runners avoid?
Before a run or the night before a big race, Eidel recommends going easy on:
Spicy foods or foods overly high in fat, which can cause GI upset
Foods that are very high in fiber, which can cause gas and cramping
Caffeine ― Although it is tempting to grab a caffeine boost right before a run, runners should remember that for some people, caffeine can stimulate the GI tract, which can result in diarrhea or the need for an emergency bathroom break
Does carb-loading work?
It might. Carb loading is the practice of eating a lot of carbohydrates ― particularly those that are easily absorbed, such as white bread, pasta and rice ― for 24 to 48 hours before a big race or distance run, to shore up your body’s stores of glycogen and lessen the risk of burnout before finishing the event.
Some studies show carb loading is beneficial for people preparing for a race, but it’s important to make sure during that time you’re also allowing your body to rest and giving it time to store what you are ingesting. The number of carbohydrate grams will be differ from person to person, but in general, evidence shows carb loading can be beneficial prior to a distance event.
In contrast, casual runners likely do not need to carb load. Ensuring that their day-to-day diets include extra carbohydrates can be sufficient.
What to Eat After a Run
It’s common for people not to feel hungry after a run, but a snack or light meal of complex carbohydrates and protein within the first hour after running can help replenish glycogen stores and to support recovery and rebuild stressed muscles. For example:
Peanut butter and banana
Egg on toast
Sandwich with deli meat
Pasta with meat or plant-based protein
Veggie burger on a bun
Protein shake or smoothie
Running to Lose Weight
If you’re interested in running as part of a weight loss plan, getting adequate nutrition is a must. Even casual running or jogging burns calories and can be hard on the body. Runners can become undernourished at first because they don’t understand how much energy they’re burning when they run and what they need to properly recover.
Eating enough is also essential to building muscles, which can aid in fat burning ― a plus for people working on achieving or maintaining a healthy weight.
For optimal weight loss, your plan should not rely on running alone but also include strength training and proper nutrition.
Listen to your body
If you run regularly, you should pay attention to the effects of what you eat and when, especially on running performance. Learning what works best for you can take some time and a little trial and error, but it is worth it, since running, jogging and other regular aerobic exercise offers so many health advantages.
Always feel free to consult a dietitian or doctor, and listen to your body if you’re not keeping up with your training goals.
A risk factor is anything that raises a person’s chance of developing heart disease and stroke. There are two types of risk factor, those you cannot change and, thankfully, those you can change. Up to 80% of the incidence of heart disease can be prevented by modifying risk factors such as high cholesterol, high blood pressure and smoking. The more risk factors you have, the more likely it is that you will develop heart disease and stroke. Focus on the risk factors you can change, because even if you have a family history, there is a lot you can do to reduce your risk.
Risk Factors You Can Change
The risk factors for heart disease and stroke that you can change are all related to your lifestyle. Simple changes, for example what you eat, can help reduce high cholesterol. Taking more exercise can help reduce your blood pressure and your weight. You should be aware of your risk factors for heart disease and stroke and take the necessary steps to reduce them.
