Can Exercise And Food Boost Your (And Your Clients') Immune System?


Jul 31, 2020

By Tim Saye

It can sometimes seem like there are a lot of companies preying on anxieties about becoming sick, suggesting that certain foods, or supplements or specific methods of training can "boost" someone's immune system. 

The immune system is a complex biological system working to protect us from germs and disease from the environment and people around us. It is not a single entity that can be targeted by a highly marketable potion. It's attractive to think that our immune system can be boosted, particularly when a lowered immunity can lead to picking up diseases and becoming unwell. 

Research done at Harvard into the lifestyle factors which contribute to a robust immune system does include exercise and generally healthy diets. However, it's worth mentioning that giving "immune-boosting workouts and nutrition plans" fall into the category of medical advice, and probably far beyond the scope of most personal trainers.

In this article, we'll go through the basics you should know about the connection between nutrition, exercise and the immune system so you can educate your clients to make better choices too. In an upcoming blog, we'll dive into exercise options and nutrition choices that support the immune system better than others.

The First Line of Defence

Choosing to follow a healthy lifestyle is one of the best methods of protecting your immune system - and giving that advice to your clients is definitely within your scope of practice as a personal trainer. 

Healthy living strategies could be as simple as giving up some habits that are actively damaging to someone's immune system. These could include giving up smoking, limiting alcohol and doing what you can to minimise stress. You can also highlight the importance of regularly washing hands and restricting exposure to germs. If you run a gym or a personal training studio, you'll have processes in place to inform your members on these too.

You can also support clients in adding in some behaviours which would help their body get the nutrients it needs. This could include eating a diet that's rich in protein, fruits and vegetables in quantities that allow them to maintain a healthy weight and getting enough restful sleep.

"Boosting" Your Immune System

Scientifically, it doesn't make much sense to try to boost your immune system. Increasing the number of immunity cells - or any cells - in your body can lead to further health complications in itself. Immunity is a particularly complex area because so many different types of cells are involved in the immune response. Even if we could know which types of cells we should boost for the best levels of protection, which we don't, we don't know what combination of cells is optimal for immune system response anyway. 

Even if we could boost the immune system, adding more cells into an already functioning system can put too much pressure on it. In the case of the immune system, that could lead to inflammation or autoimmune diseases. So be cautious about recommending any plans or supplements which claim to boost the immune system to your clients - or falling for such scams yourself. 

Avoid Extreme Exercise & Fad Diets

If you are concerned about your immune system, or that of your client, taking on an intense exercise regime or a drastic dietary change may add to their stress. Advising your clients to approach both diet and exercise with an attitude of moderation will be advisable - particularly during times of high stress. Managing stress levels is a crucial part of staying healthy. If they are unused to high-intensity exercise, it may not be the best time to start an intense training regime, especially if they've been inactive for some time. 

The evidence that any nutritional intervention can help the immune system is weak, and there's not a great deal of research into the impact of nutrition on the immune system in humans at all. The most compelling evidence seems to relate to avoiding nutritional deficiencies instead. You and your clients can achieve that through a balanced diet, which includes a variety of fruits and vegetables. This will help to ensure adequate intake of essential nutrients with little risk of excess consumption of any single nutrient. 

If your client's diet is deficient in a single nutrient, supplementation may be advisable. It's common in clients who have food allergies and intolerances or choose to stick to a limited diet like vegans. But this won't be the case for all clients, and blanket supplementation should be avoided as unnecessary and sometimes expensive. With vitamin supplementation, more is not necessarily better, and it's highly dependent on personal context. If necessary, advise your client to speak to their doctor or a dietitian if they are concerned about nutrient deficiencies in their diet.

Your best approach is to encourage your clients to stay focused on health-promoting behaviours at home, including creative cooking, spending time with loved ones, and making time for relaxation. These will all compliment a healthy, nutrient-dense diet and enjoyable exercise routine and contribute to feelings of wellness. Advising your clients about the importance of being consistent with these less glamorous aspects of their health will have a compound effect on their long term well being. 


There are no exercises or foods which can "boost" your immune system - and that's a good thing. A boosted immune system is one which is overworked and inflamed. Instead, encouraging your clients to lead a healthy lifestyle more generally will support their immune system and their overall health. 

You can advise them to include regular exercise through an activity that they enjoy (not necessarily something high intensity). Preparing and eating nutritious foods, that are high in protein and vitamins will benefit your immune system to function at its best. If your clients aren't ready to add anything into their healthy routine yet, they could get a lot of benefits from simply removing the behaviours which are damaging their health. 

As a personal trainer, your role in supporting your clients will be to encourage a generally healthy lifestyle. Helping your client as they manage their nutrition and exercise in the context of what's enjoyable and manageable for their experience level will be necessary to their long term commitment to their health. If you or your clients feel concerned about their immune system, your client could be directed to their doctor, or health care professional to establish if there are any deficiencies before deciding on their next course of action.