Athletes who’ve found their stride this summer will need to keep pace in the fall. But as science and experience show, this is the season where most of us catch colds and infections, leaving us hitting the sickbed more frequently than the gym.

There are several reasons for this. The main one is that cold and flu viruses are best transmitted at cool temperatures. But a weak immune system is typically at the bottom of any onslaught of the sniffles.  

So if you’re aiming for a Spartan Race in the coming months, here's how to boost your immune system naturally this fall to ensure you’re ready to rock your race come rain, hail, or snow.

How to Boost Your Immune System Naturally

Go Outdoors

Regular exercise is a known sickness slayer and contrary to what some people might think, the more you can do it outside the quicker you’ll build up a healthy immune system. 

“The fall is really the ideal season to start training,” says Chardét Durbin, a Brazilian-American fitness instructor and founder of online health and fitness brand, Corpão. “You don’t have the excessive heat of summer or the other, colder extreme of winter. So you can use the autumn days to get used to moving in colder weather, and build up a consistent training routine.”

Also, exercising out of doors means greater exposure to sunlight, the main provider of immune-supporting vitamin D. And while the sun in autumn can be weak, even exercising for as little as 20 minutes outdoors in sunlight can up your D dosage. 

How to Make It Happen

Chardét, who used to run an outdoors boot camp in New York’s Central Park recommends that both beginners and competent athletes focus on endurance exercises.

“High-intensity sprints followed by a slow jog or some sort of circuit training is a type of programming that challenges your body, forcing it to adapt, then evolve, making you better and stronger.”

She also recommends using public furniture and ‘nature’s equipment’.

“You can do assisted push-ups and lunges using a park bench, wall-sits against trees, or bring a mini resistant band to do lower squat walks, plank walks, and chest flies between short sprints. Use the unexpected outdoor terrain too so that you’re really utilizing many of the elements of fitness such as balance and core control.”

Related: 6 Smart Secrets to Build Endurance for OCR

Mind Your Gut

Good gut health is a fast-track to being flu-free, according to several studies. Around 70 percent of our immune cells live along the gastrointestinal (GI) tract, with our intestines, in particular, containing bad bacteria-blitzing microbes. 

But according to Natalia Shulzhenko, an assistant professor and physician at the Oregon State University, “There's an increasing disruption of these microbes from modern lifestyle, diet, overuse of antibiotics and other issues.”

Writing in Clinical Reviews in Allergy and Immunology, Shulzhenko notes that when this disruption occurs, communication between the immune system and gut bacteria breaks down, and, alongside influenza, can lead to more worrying diseases such as inflammatory bowel disease, Type-2 diabetes, and metabolic syndrome. 

How to Make It Happen

A healthy gut boasts a diversity of microbes, each of which prefers different and fibrous foods. So include lots of plant-based foods and probiotics such as live yogurt, sauerkraut, miso, and kombucha on the menu. 

Studies on animals have suggested that stress also plays a large part in disrupting good gut health. Making room for regular exercise, avoiding unhealthy habits like smoking, and getting a good night’s sleep can all help when figuring out how to boost your immune system naturally. 

Cut Back on Sugar

We all know refined sugar’s reputation as a major cause of obesity and several chronic diseases. But did you know your sweet tooth can lead to the chills too? A report on WebMD claims that consuming too much sugar stops immune system cells attacking bad bacteria in the body, an effect that can last a couple of hours after you’ve slurped back a soda. 

“But it’s important to be smart about sugar intake, especially if you’re working out outdoors and in the autumn,” adds Chardét, who is also a qualified nutritionist. “Strip out processed sugars, but remember that simple natural sugars, like whole fruits, are part of the good carbs you need for your body to run efficiently.”

How to Make It Happen

Chardét advises card-carrying sugar lovers to cut back in steps, acknowledging that it can be difficult to go cold turkey when it’s cold outside. 

“The fall is when people naturally crave high-calorific food, as from an evolutionary point of view we store more fat in the fall and winter. If it’s difficult for you to stop eating sugar, start by stripping out sauces, condiments, and other foods that you won’t miss as much daily and which, surprisingly, contain a lot of sugar.”

Related: 5 Secret Sugar Bombs Athletes Shouldn’t Eat

Partner Up

Strange as it may sound, people with strong social connections also have a strong immune system. In one study carried out by a team at Pittsburgh’s Carnegie Mellon University, people with a wide range of social ties were significantly less likely to catch colds than those with few social networks. 

Author of the study, Dr. Cohen, told The New York Times that diversity within the social network is key as it ensures the individual has several outlets to discuss or escape causes of stress. Additionally, it was suggested that exposure to more germs may work to stimulate a person's immune system, making them hardier in the long-run.

How to Make It Happen

Don’t let the frosty shift in the season turn you into a fall recluse. Take time out with friends and family, or widen your social circle by volunteering with a charity or community group. Join a club that’s focused on a favorite hobby or pastime. And – need we say? – Sign up for a Spartan Race and feel the fun and friendliness that the events are world-famous for.

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