Do you wish there was a way to fire up your metabolism? There are lots of claims that such-and-such a product, food, or supplement can do that. Unfortunately, it’s not that simple. Your resting metabolism, or that rate at which your body burns energy at rest, is largely determined by genetics. You’ve probably known people who could eat what they wanted and never seemed to gain weight. That’s the power of genetics. Age is a factor too. Those people who can gobble up anything and see no change in their body weight are usually young. But, once you get past the age of 30, resting metabolic rate begins to slow. That’s one reason people start to gradually put on weight after age 30.
Is there anything you can do about this frustrating, metabolic slowdown? You may have heard that strength-training is a key to boosting your metabolism and that working out with weights revs up the rate at which your body burns energy. Is there truth to this? What does science say about weight training and metabolic rate?
What Constitutes Your Metabolic Rate
What do we mean when we talk about metabolic rate? Your body is constantly burning macronutrients, like fat, carbohydrates, and, to a lesser degree, protein, to fuel your body’s myriad activities. Even when you’re asleep, your body continues to burn stored fuel, like glycogen and fat, to make energy. After all, your body never stops working even when you drift off to sleep. The rate at which your body uses energy when you’re resting or asleep under standardized conditions is called your basal metabolic rate. It’s the energy required to keep your body temperature high enough and provide energy for critical functions like breathing and organ function.
Resting metabolic rate is similar to basal metabolic rate. The difference is basal metabolic rate is harder to measure as you must be at a complete state of rest, have not eaten recently, and be in a room at a certain temperature. That’s why it’s only used in laboratory settings. Instead, researchers use resting metabolic rate, more easily measured, as a proxy for basal metabolic rate.
The other components of metabolism include activity thermogenesis, the energy you burn during exercise, and the thermic effect of food, the additional calories your body expends to digest and absorb food. Resting metabolic rate makes up the bulk of your energy expenditure every day, between 60 and 75%. No wonder we want to power it up!
Can Strength-Training Boost Your Resting Metabolic Rate?
Several studies show that resistance training can modestly boost resting metabolism. In one study, healthy, but not trained, adults over the age of 65 took part in a 26-week resistance training program. They trained using a resistance appropriate for muscle hypertrophy, between 65 and 80% of their one-rep max. Each participant did a total body workout with an emphasis on compound lower body exercises and used progressive overload to gradually increase the challenge.
The results? When the researchers measured their resting metabolic rate and compared it to their resting metabolism before the program started, they saw a significant difference. The participants had a resting metabolism that was 7% higher. While this may not sound like a huge increase, it would be roughly equivalent to burning an extra 100 calories per day.
Another study carried out in 2012 came to a similar conclusion. After 10 weeks of resistance training, participants showed a 7% increase in resting metabolic rate. They also enjoyed other “perks” such as an increase in walking speed, improved functional performance, weight loss, enhancement in cognitive abilities, and more confidence. So, resistance training does seem to modestly boost resting metabolic rate.
In fact, resistance training is a better bet for boosting metabolism than endurance exercises, like running, cycling, and brisk walking. How do we know this? In one study, healthy males were divided into three groups. One group resistance trained using weights, a second did only endurance training, while the third did a combination. The endurance training group had the most disappointing change in resting metabolism. They experienced a decrease of around 2%. That’s going in the wrong direction! More encouragingly, the resistance training group enjoyed a 6% rise in basal metabolic rate and the combination group 5%.
Strength-Training to Boost Resting Metabolism
If you think your resting metabolism is idling along at a snail’s pace, grab a pair of weights! To get the most benefits, lift heavy. Working your muscles using heavy resistance ramps up key hormones and chemical messengers, including adrenaline and noradrenaline, that increase your heart rate and transiently increase the rate at which your body burns energy. It also stimulates the release of growth hormone and testosterone, assuming you work hard enough. In general, lifting at between 65% and 80% of one-rep max is best for building metabolically active muscle and boosting resting metabolism.
Make sure you’re doing the big, compound lifts too, such as squats and deadlifts. These exercises work multiple muscle groups and are the most effective at building muscle and ramping up your metabolic rate. Compound lifts, using a challenging resistance, also increases excess post-exercise oxygen consumption or EPOC. Another name for EPOC is the afterburn and it’s the extra calories your body burns to recover from an intense training session. This transient increase in metabolism can last for a few hours or, based on some studies, up to a day or two. Keep in mind that some studies suggest that the afterburn is overstated and isn’t significant enough to contribute to weight loss.
Another Reason to Strength train
The most important reason to strength train is to preserve the muscle you already have. You gradually lose muscle after the age of 30 and the loss speeds up as you enter late middle age. That partially explains why resting metabolism slows with age. Also, by strength-training, you’ll be stronger and more functional. So, strength training is a definite win when it comes to staying youthful and avoid age-related weight gain. Take advantage of it!
Curr Sports Med Rep. 2012 Jul-Aug;11(4):209-16.
Exercise After-Burn: Research Update. By Chantal A. Vella, Ph.D. & Len Kravitz, Ph.D.
Journal of Applied Physiology. 89. pages 977 -984. (2000)
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