Here's What Happens to Your Body if You Exercise for 15 Minutes Every Day

Woman exercising outdoors

Marathon season reaches its peak mid-fall. If you watched from your couch this year, wondering how anyone could ever run for that long, experts want you to know you don't have to spend hours running a 26.2-mile race to reap the benefits of physical activity.

"Too often, people feel they don’t have time to exercise because they think they have to go to the gym for an hour to reap the health benefits, but they don’t," says Katie Lawton, MEd., an exercise physiologist with Cleveland Clinic Rehabilitation and Sports Therapy.

But what if you only have 15 minutes? Is it worth it?

"I always say that 15 minutes is better than 0 minutes," says Stan Kravchenko, personal trainer, founder and leader trainer at OneFit.

Why is that, and how do you know if you're working out enough or too much? Experts share what happens to your body when you log 15 minutes of exercise daily. 

Related: What Happens to Your Body If You Run Every Day 

What Happens to Your Body if You Exercise for 15 Minutes Daily

The American Heart Association recommends 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity per week. Lawton echoes these recommendations, but what does vigorous or moderate-intensity actually mean?

"Vigorous-intensity exercise can be thought of as an intensity where you are not able to hold a conversation," Lawton says. "Moderate-intensity exercise can be described as you can hold a conversation, but raising your voice would be a challenge."

Fifteen minutes per day, seven days per week equals 105 minutes per day—that's between 75 and 150 minutes. Where should you fall on the intensity scale, then?

It depends. "For those who've been active and have the experience exercising, I suggest starting with vigorous intensity training at 70% of your max heart rate, gradually increasing the intensity week by week," Kravchenko says. "This approach ensures progression and keeps the routine enjoyable."

For example, Kravchenko says an experienced runner can try maintaining their heart rate at 70 percent for 15 minutes and increasing it to 85 percent the following week.

However, this method may be challenging for others. "If someone is recovering from burnout, for example, I wouldn’t want them to put more stress on their body by exercising vigorously and would instead recommend that they stick to gentle movement and moderate-intensity exercise," says Rachel Lovitt, a certified personal trainer and mobility specialist.

Lovitt adds that your ability to hit specific intensities may vary day by day. Regardless of where you are, experts share it's important not to compare yourself, especially to professional athletes who stay fit for a living.

"Professional athletes have the time to eat, train, sleep and repeat," says Kirk Anderson, a certified Fitness Coach and ISSA Nutritionist. "They don’t miss cardio days because they have to go to work in the morning." 

What's more, your 15 minutes of movement per day offer perks too. "Benefits include improved cardiovascular health, increased bone density, mental clarity, mood enhancement, a stronger immune system, better joint health, increased metabolism and improved blood sugar control," Kravchenko says.

In fact, studies have shown that 15 minutes per day of exercise increases life expectancy. Heck, a 2022 study indicated that just 15 minutes of weekly vigorous-intensity exercise could lower your chances of premature death. 

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Signs You're Working Out Too Much

Fifteen minutes of exercise daily may not sound like much. However, fitness regimens often include a rest day or two. Is it safe to work out for 15 minutes per day? It depends, but generally, yes.

"You can work out for 15 minutes per day every day," Anderson says. "I would recommend once or twice during the week that the exercise be low intensity, such as walking, to give your body a break."

Still, you'll want to be on the lookout for red flags that you may need a break. "A decline in performance, fatigue, lack of appetite, getting sick often, excessive muscle soreness and mood disturbances can all be signs you are working out too much," Lawton says.

In other words, it's highly individual, so tune into yourself and out the noise.

"As long as you are listening to your body and adjusting your movement to your energy levels and current circumstances, it is healthy to work out 15 minutes per day," Lovitt says. "Pay attention to the signs of overtraining, and never opt for exercise over sleep." 

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Signs You Could Use More Exercise

While 15 minutes per day of exercise can offer benefits, experts share that sometimes, your body may be craving more—whether it be a longer duration or higher intensity.

"If you happen to be working out and feel that you can carry out a conversation the entire time, that’s a clear sign you aren’t keeping that heart rate up," Kravchenko says. "If you aren’t sweating enough or don’t feel the tank emptying, it’s time to add some intensity."

With that in mind, only you can tell. "Be honest with yourself," Lawton says. "After the workout, ask yourself if you think you could have pushed harder."

Regardless of how long you spend working out, you want that time to offer value.

"You want to feel that you are getting a meaningful, focused workout that makes you feel empowered and energized afterward," Kravchenko says. "This process of challenging your body also challenges your mind so that you can leave the workout feeling a sense of accomplishment."

Next up: If You Only Have an Hour a Week to Work Out, Here's Exactly What You Should Do