The summer can have its downsides when it comes to your physical health. Not only does it seem like the temptations are stacked against you — looking at you, backyard cookouts, ice cream cones and happy hours — it may appear like you’re not making any fitness or weight loss progress. It turns out there may be a reason you feel that way.
According to Sharon Palmer, a registered dietitian nutritionist based in California and owner of the blog The Plant-Powered Dietitian, your metabolism might slow down slightly when it no longer has to produce heat. This means it might be a little slower in the toastier months when your body is already warm, compared with the winter months.
“Think of our bodies like a furnace — we stoke it with fuel (food) to keep it warm,” she said. “When it’s colder, we have to add more fuel to compensate for the energy required to produce heat.”
Debra Sheats, an assistant professor in foods and nutrition at St. Catherine University in Minnesota, said that because the environmental temperature is so close to your body’s internal temperature (typically around 98.6 degrees), your metabolism slows down by about 10 percent. But that’s not the only thing that could be inhibiting your goals.
“When it is very hot and humid outdoors, we have a tendency to not go outside as much to walk, bike or jog,” Sheats said. “Instead, making the choice to stay inside with the cool air conditioning may mean more time spent at sedentary activities such as reading or activities involving screen time.”
And if you do decide to venture outdoors, the tool that keeps you cool, AKA drinking water, may also cause a little weight fluctuation. John Castellani, a researcher at the Thermal and Mountain Medicine Division of the U.S. Army’s Research Institute of Environmental Medicine, found that a person’s body weight may increase by as much as several pounds in the summer due to increased water in the body.
While a person’s daily water needs depend on how much time they’re spending outside and their level of activity, hotter and humid temperatures make you more likely to sweat. Since the clothes you wear make it hard for sweat to properly evaporate and cool you off, you end up requiring more water retention to lower your internal temperatures. This process is your body’s way of adapting to the negative effects of heat stress. It happens more in people who are engaging in regular physical activity outside than those who spend their time indoors in the A/C.
But don’t let this keep you from getting your daily H2O. Sloane Davis, a certified nutritionist, personal trainer and owner of the blog Pancakes & Pushups, said not drinking enough water can be just as bad and detrimental to your overall health.
“We sweat more during the summer months,” she said. “If you don’t drink enough water, the body becomes dehydrated, slowing it down and decreasing the metabolism.”
So, what can you do?
Hot weather may have a minor effect on your body in some cases, but there are ways to counteract these hurdles. Davis said one of the ways you can speed up on your metabolism on your own is through regular exercise in the summer months.
“Incorporate resistance training along with some low-intensity cardio four to five days a week,” she said. “Get a good night’s sleep and drink plenty of water, preferably cold water.”
When it comes to exercising in the heat specifically, Sheat recommended working out early in the morning or late in the day when it’s cooler. Or, if you want to avoid the outdoors altogether, try doing at-home yoga or finding an online workout with weights. You can also go to fitness centers or workout studios to stay in the air conditioning.
No matter how you chose to exercise or maintain healthy habits, it’s crucial not to let small, external factors deter you from your goal.
“It’s important to keep in mind that there may be only small differences in metabolic rates during the year,” Palmer said. “Given our modern lifestyle with cushy air-conditioned and heated homes that keep them at a perfect 72 year-round, we may not really experience significant metabolic rate variations.”
Jill Weisenberger, a registered dietitian nutritionist in Virginia and author of the book Prediabetes: A Complete Guide, said that weight loss is too complex for something like temperature to have a major effect on. As long as a person has the right mindset and is willing to focus on the process and not just the pounds, losing weight during the summer is totally possible.
“I think that sometimes people put an emphasis on teeny tiny things,” Weisenberger said. “It’s so much smarter to use your energy — which is a limited resource — on something that’s really important, like eating regular meals and getting a good night’s sleep... People measure their water and they worry about the temperature and it takes away the energy from things that really make a difference.”
In other words, if being healthy during the summer is your goal, then a little metabolic difference or slight change in your body ― or any time ― shouldn’t stop you.