How much you should exercise to live longer, according to a new study

Here's what to know about this new study—and how a balance of strength training and aerobic exercise could benefit you in the long run.

Key Points

• Strength training for 90-119 minutes weekly may lower all-cause mortality by 13% and neurological disease risk by 27%.
• Combining aerobic exercise with resistance training offers the greatest benefits, reducing death risk by up to 45%.
• Meeting physical activity guidelines can improve longevity; start small and build consistency over time.

You probably already know that strength training can increase muscular strength and mass, which can help improve balance and posture—not to mention give you the muscle power to move through your day like a pro. Resistance training can also help you maintain a healthy weight and may help improve your blood pressure and cholesterol levels, some research has suggested. 

Seems like a lot of great reasons to pick up those dumbbells, but Harvard researchers wanted to know more. They took a deep dive into three large long-term studies to see if strength training alone (or strength training paired with aerobic exercise, like running) could reduce the risk of dying from any cause and from specific diseases, including cardiovascular disease, cancer and neurological diseases, like Alzheimer's. Plus, they looked at how much strength training showed potential benefits related to this topic, if any.

The study results were recently published in the British Journal of Sports Medicine. Let's break down the study and what they found.

How Was This Study Conducted?

For this study, data were drawn from the Health Professionals Follow-Up Study, the Nurses' Health Study and the Nurses' Health Study II. These are all long-term studies that followed participants for up to 30 years, collecting data on their demographics, lifestyles, health habits (including diet and exercise), medical diagnoses and deaths.

From these studies, researchers collected data on almost 150,000 people, about 80% of whom were women. Between all three original studies, the average age of participants at baseline was 54. Participants completed questionnaires every couple of years, reporting how often and for how long they exercised, including resistance training and aerobic activities such as walking, running, swimming, cycling and playing tennis. They also completed food frequency questionnaires and self-reported weight and height for BMI calculations.

Confounding factors that were adjusted for during statistical analyses included race, age, BMI, smoking status, alcohol intake and family medical history (including for heart attack and cancer). Women also reported menopause status and postmenopausal use of hormones. During the study periods, there were almost 36,000 deaths; researchers used the causes of death for this study to see if there were any connections between causes of death, resistance training and aerobic exercise.

What Did This Study Find?

After adjusting for potential confounding factors and aerobic exercise, researchers found that performing 90 to 119 minutes of long-term resistance training per week was associated with:

• 13% lower all-cause mortality (death from any cause)
• 19% lower risk of dying from cardiovascular disease and events
• 27% lower risk of dying from neurological disease, like dementia

Benefits leveled off after 119 minutes per week, with no additional benefits in these specific cases.

Additionally, doing 7.5 MET-hours of aerobic activity per week was associated with a 26% to 43% lower mortality risk compared with people who got less than 7.5 MET-hours per week. METs are a measure of work performed—7.5 MET-hours per week is equivalent to standard physical activity recommendations—150 to 300 minutes per week of moderate-intensity activity or 75 to 150 minutes per week of vigorous physical activity.

But what showed the greatest benefit for preventing death was combining high levels of resistance training and aerobic exercise. For example, researchers calculated a 45% lower risk of death for those performing 30 to 45 MET-hours per week of aerobic exercise plus 60 to 119 minutes per week of resistance training.

Those who engaged in the highest amounts of aerobic exercise (≥45 MET-hours per week) had a 42% to 47% lower risk of death, regardless of their resistance-training level. For reference, 45 MET-hours per week looks something like walking at a 15-minute-per-mile pace for more than an hour, seven days a week.

Limitations of this study include that most of the participants' information was self-reported. This leaves lots of room for inaccuracies, forgetfulness and miscalculations, including under- and overreporting of data (such as underreporting alcohol intake and overreporting exercise amounts). This study measured traditional resistance training but did not include other types of strength-training activities, such as calisthenics and Pilates. It also didn't include the intensity of the resistance training workouts. Lastly, caution should be used when generalizing these results, as the cohorts were primarily white, middle-aged health care professionals.

How Does This Apply to Real Life?

Current physical activity guidelines recommend getting 150 to 300 minutes per week of moderate-intensity activity or 75 to 150 minutes per week of vigorous-intensity activity, plus at least 2 days of strength training. The results of this study suggest that meeting the minimum requirements for aerobic activity and strength training may help lower the risk of death from any cause. Specifically, this study found the greatest benefits with about 90 minutes to two hours of strength training per week. And while some guidelines don't include stretching, many notable organizations, such as the American College of Sports Medicine, also encourage flexibility training (stretching) at least 2 days per week and, ideally, every day.

If you're nowhere near meeting these guidelines, that's okay. Just start where you're at and slowly increase frequency, intensity and duration over time. Whether you choose to go it alone, hire a personal trainer or work out with a buddy or in a group, the key is consistency, as consistent practice is essential to building long-term habits.

While dumbbells, resistance bands and weighted balls are handy and will help you increase the intensity of your strength training workouts over time (and banish boredom), including body weight exercises is a great way to get started if you have no equipment. This might include a variety of squats, lunges and push-ups, as well as triceps dips, planks and pull-ups. Following a yoga routine is a great strength training workout that also includes stretching.

You’ll also want to include cardio exercise, and there are a slew of aerobic activities to choose from, with walking being the simplest for many. Mix it up with a game of pickleball, a hike on a local trail or an indoor cycling class. Or simply crank up your favorite music and dance.

Our Expert Take

This study suggests that resistance training and aerobic exercise, both individually and together, may reduce the risk of dying from any cause and from cardiovascular and neurological diseases. There were also some observed benefits from lower levels of resistance training and cancer mortality risk. Exercise is one important piece of the wellness puzzle, along with eating a balanced diet, getting healthy sleep and managing your stressors. Start replacing less beneficial habits with more beneficial ones to improve both the quality and length of your life. And be consistent with the changes, no matter how small they are. Over time, small changes add up to big benefits.

Read the original article on EatingWell