Exercise can increase your resting metabolic rate, but the type of exercise matters enormously. Resistance training has the strongest evidence, raising resting metabolism by roughly 96 calories per day on average compared to not exercising. Aerobic exercise alone tends not to budge resting metabolism unless it’s intense enough or sustained over years. Understanding why requires looking at what resting metabolic rate actually depends on and how different forms of exercise change those variables.
Your resting metabolic rate (RMR) is the energy your body burns just to keep itself alive: breathing, circulating blood, maintaining body temperature, repairing cells. It accounts for 60 to 75% of the total calories you burn each day, which is why even a modest increase can add up over time.
Resistance Training Has the Strongest Effect
A systematic review and meta-analysis of exercise interventions found that resistance training increased resting metabolic rate by an average of about 96 calories per day compared to non-exercising controls. That may sound small, but it’s a persistent, around-the-clock increase that compounds over weeks and months.
The primary reason is muscle. Muscle tissue burns roughly 4.5 to 7 calories per pound per day at rest. Fat tissue burns far less, somewhere around 50 to 100 times less than muscle per unit of weight. When you add muscle through strength training, you’re essentially installing a larger engine that idles at a higher rate. But muscle alone doesn’t explain the full picture. Your internal organs (brain, liver, kidneys, heart) are metabolically ravenous, burning 15 to 40 times more energy per unit of weight than muscle. Exercise doesn’t grow these organs, but it does influence hormonal and cellular processes that affect how efficiently they operate.
How long before you see results? A nine-month resistance training program produced roughly a 5% increase in resting metabolic rate on average, though individual responses varied widely. Some of that variation was explained by differences in how much muscle people gained and by changes in thyroid hormone levels. Shorter programs of around 20 weeks have also shown measurable increases in previously sedentary people, so you don’t necessarily need to wait nine months, but the effect builds gradually.
Aerobic Exercise Alone Often Falls Short
Steady-state cardio, like jogging or cycling at a moderate pace, is excellent for cardiovascular health and calorie burning during the session itself. But its effect on resting metabolism is disappointing when studied in isolation. One well-controlled trial found that after an aerobic training program, fat-free mass, whole-body protein turnover, and resting metabolic rate were all unchanged. Participants lost a small amount of body weight, but their resting calorie burn stayed the same.
The reason is straightforward: moderate cardio doesn’t typically add muscle mass, and it doesn’t produce the same hormonal aftereffects that resistance training does. Without a change in the body’s composition or hormonal environment, the resting metabolic rate has no reason to shift upward.
That said, long-term endurance training at high volumes tells a different story, particularly when it comes to aging. In women who had run competitively for around 18 years, the typical age-related decline in resting metabolism (adjusted for body composition) was completely absent. Competitive older female swimmers showed the same preservation. For men, the picture was slightly more nuanced: resting metabolism still declined with age despite chronic endurance exercise, but when researchers matched older and younger men for training volume and calorie intake, the difference disappeared. The decline was tied to doing less exercise and eating less over time, not to aging itself.
The Afterburn Effect Is Real but Temporary
After a hard workout, your body continues burning calories at an elevated rate as it repairs tissue, clears metabolic byproducts, and restores its systems to baseline. This is sometimes called the “afterburn” effect. Both resistance training and high-intensity interval training produce a measurable version of it.
In one study of fit young women, a 30-minute circuit-style resistance session and a 30-minute high-intensity interval session on a treadmill both elevated energy expenditure for at least 14 hours afterward. At the 14-hour mark, participants were still burning about 3 extra calories every 30 minutes compared to their baseline. Estimated over the full post-exercise window, each session produced at least 168 additional calories burned beyond the workout itself.
By 24 hours, though, the elevation had disappeared entirely. Neither protocol sustained a change in resting metabolic rate past that point. So the afterburn is a real bonus on training days, but it’s not a permanent metabolic shift. The lasting change comes from what exercise does to your body composition and hormonal profile over months, not from what happens in the hours after a single session.
Hormones Play a Supporting Role
Exercise influences resting metabolism partly through hormones, particularly stress hormones called catecholamines (epinephrine and norepinephrine). In a study of highly trained endurance athletes, when training was suspended, levels of these hormones dropped significantly, and resting metabolic rate fell along with them. Thyroid-stimulating hormone rose during the break, but free thyroid hormone levels didn’t change, suggesting that the catecholamine drop was the more likely driver of the metabolic slowdown.
This finding reveals something important: part of the metabolic boost from regular exercise isn’t structural (like added muscle) but physiological. Your body maintains a slightly elevated hormonal “idle speed” when you’re training consistently. Stop training, and that idle speed drops. This is one reason why consistency matters more than any single workout.
Exercise Protects Your Metabolism During Dieting
One of the most practical applications of this relationship shows up during weight loss. Severe calorie restriction reliably tanks your resting metabolic rate. In a study of obese participants eating just 500 calories per day, resting metabolism dropped to about 87% of its pre-diet level after two weeks. That’s a significant slowdown that makes continued weight loss harder and regain more likely.
When those same participants added 30 minutes of daily moderate exercise while continuing the restricted diet, their resting metabolic rate climbed back up to pre-diet levels within two weeks. The exercise essentially reversed the metabolic adaptation that dieting had triggered. This doesn’t mean exercise cancels out the calorie deficit; it means it helps prevent your body from downshifting into a lower-burning state that sabotages long-term results.
What This Means in Practice
If your goal is a higher resting metabolic rate, resistance training is the most direct path. It builds the metabolically active tissue that raises your baseline calorie burn, and it produces favorable hormonal changes that keep your metabolism running slightly higher around the clock. Aim for consistency over months, not weeks. Measurable changes in resting metabolism typically emerge after several months of regular training, and the effect grows as you gain more muscle.
Adding high-intensity work, whether through intervals or circuit-style lifting, earns you a bonus on training days through the afterburn effect. Steady-state cardio, while valuable for many other reasons, is unlikely to raise your resting metabolism on its own unless you sustain it at high volumes over years.
If you’re also restricting calories to lose weight, exercise becomes even more important as a metabolic safeguard. It helps keep your resting metabolism from cratering in response to the calorie deficit, which makes a meaningful difference in how sustainable your results are over time.