Health / Expert Advice

Why Do I Feel So Tired During the Summer?

Falling asleep while poolside? This could be why.

It’s not just your imagination—summertime can be exhausting. Sometimes the culprit is obvious (say, an outdoor run or a busy vacation). But other times it’s mind-bogglingly unapparent. No matter what we do, we often end up feeling fatigued. To get to the bottom of this lack of energy, Aaptiv spoke with Dr. Joel Seedman, neuromuscular physiologist, performance specialist, and owner of Advanced Human Performance, and Jonathan Cane, exercise physiologist and co-owner of City Coach Multisport. Read on as we unpack the reasons behind the lack of energy this time of year.

Your body is acclimating to the heat.

If you blame the heat time and time again for your unusual lack of energy (guilty), you’re actually not in the wrong. “Heat acclimation plays a large role when it comes to how well our bodies handle heat,” Seedman points out. “This isn’t something that happens overnight. It can take several weeks to become fully adapted to the heat, particularly when it comes to our body’s physiology. One of the key adaptation responses to heat is that our bodies learn to sweat better and more efficiently as a means of cooling us down.”

If you thought sweating was just an inconvenience of being in the hot sun, think again. Sweating serves to keep us cool, whether we’re in the heat or working out. The hot summer months take sweating up a notch. “When we’ve not fully adapted, this same perspiration response won’t be there,” Seedman explains. “As a result, our body temperature can become excessively high, making us feel unusually fatigued and drained. Not to mention, there’s a greater chance of heat exhaustion and heat stroke.” To prevent this, seek out shade and cool areas often, especially if you feel faint or nauseated.

Your metabolism has slowed down.

Many people don’t know that a change in seasons has an effect on metabolism—and thus energy level. “This is always a shock to most folks. But during [these warmer] periods our metabolism actually runs slower than it does when it’s cold,” Seedman says. “When we’re cold our metabolism must work overtime to help keep our body temperature elevated, which involves significant caloric expenditure. The opposite occurs in the heat, as our temperature is already high enough. Therefore, the metabolism will slow down to accommodate for this as a means of ensuring we don’t overheat. This slower metabolic rate can oftentimes make individuals feel unusually tired and lethargic, oftentimes resembling sleepiness and lack of energy.” Though this side effect may be irritating, it’s great to know our bodies make sure we don’t overheat (which is much more dangerous than an afternoon nap).

One way to keep your metabolism up and running is with a regular strength training routine, and Aaptiv can help you get started.

You’re burning more calories when exercising.

“Exercising or performing physical activity in the heat actually burns more calories than other climate conditions,” Seedman tells us. If you’ve ever taken running or cycling outdoors, you can imagine why. “Our bodies tend to fatigue more rapidly, involving a relatively higher heart rate response, and thus require more ATP (or energy) expenditure to maintain physical activity levels,” he adds.

In short, our bodies get tired faster in the heat. Because of this, you’ll need to put in more effort to keep up with your workout. “This increased caloric expenditure can cause more fatigue than normal. It oftentimes promotes feelings of fatigue and exhaustion after exercise or physical activity that can last for hours and sometimes days, depending on the intensity,” Seedman says. Likewise, our bodies deal with what Cane calls a supply-and-demand struggle. He explains, “Your working muscles need blood to deliver oxygen. But your body still wants to send blood to the skin for cooling and sweating. Since you have a finite blood supply, workouts will also be harder in the heat.”

If you find it too hard to workout outdoor, try an indoor workout with Aaptiv. We have classes for indoor cycling, the elliptical, the treadmill, the stair climber, and much more.

Similar to overexercising, it’s important to note when the circumstances you’re exercising in are too intense. If you notice any signs of extreme exhaustion or feel faint while working out outdoors, stop immediately. Find a cool place to rest, get hydrated, and call a doctor if needed. To prevent any accidents, keep an eye on the temperature, and use your discretion.

You’re dehydrated.

Speaking of staying hydrated, not doing so can be one of the reasons you feel so worn out. “In the heat, one byproduct of the increased temperature could be dehydration. If not in a clinical sense, certainly in the low-level, chronic, less-than-optimal hydration sense,” Cane says.

As you can likely guess, dehydration leads to exhaustion. “Dehydration is a critical component that often leads to excessive fatigue and lack of energy when it comes to how individuals handle the heat,” Seedman states. “In hotter climates, individuals are more likely to become dehydrated due to the body’s adaptive mechanism of perspiration and sweating.” Remember how we discussed sweating earlier? Well, due to the body sweating more to keep you cool, it loses water faster than usual. “This can lead to electrolyte imbalances and a number of physiological consequences that can promote lack of energy and even physical ailments if not properly attended to,” Seedman says. We know you hear about drinking enough water all the time, but it’s especially paramount in the hotter months. You should constantly replenish that water loss. Stay hydrated with tons of water, fresh smoothies, or juices that will keep you feeling refreshed.

You’re mentally making it worse.

We know—it’s hard to not complain about the intense heat. The weather seems to be the only thing people speak about when it’s extremely hot. It turns out, though, that you could be making it worse. “Although many heat-related conditions can be traced back to physiological disturbances, there’s also a psychosomatic component that can play a substantial role for many folks,” Seedman notes. “Simply put, many individuals simply don’t enjoy the heat and dislike the way they feel under such conditions. This psychological component can further impact the physiological effects the heat has on their body.”

In layman’s terms, complaining literally makes it worse. “For some, it can be something as simple as a general feeling (they dislike feeling sweaty and sticky). This can further contribute to an overall lack of energy due to emotional and psychological disturbances,” Seedman explains. Envision how easy it is to think yourself into a rut—this is similar. Once you’re into the mindset of how awful the heat is, it can be difficult to think of anything else. If it’s your only focus, the symptoms and side effects will feel exaggerated. In addition to staying inside or finding shade, try your best to take your mind off of the heat.

Expert Advice Health


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