We all got the exercise-is-good-for-you memo. But when it comes to which exercise does what, how to do it, and how to avoid soreness that keeps you from doing it again, questions abound. Here are some answers.
A bit of a stretch?
For generations, athletes of all ages and abilities were taught the gospel of stretching before they exercise to boost performance and prevent injuries.
“Then in the late 1990s and early 2000s, a number of reports indicated that static stretching might impair performance in activities like jumping or weight lifting,” says David Behm, a professor in the School of Human Kinetics and Recreation at Memorial University of Newfoundland in Canada.
(Static stretching is stretching without movement, like when you bend over, reach for your toes, and hold.)
“But there are problems with that research,” says Behm, who literally wrote the book on the topic—The Science and Physiology of Flexibility and Stretching.
For starters, some of the studies weren’t realistic. “In one, they looked at stretching the calf muscles for 13 repetitions of 135 seconds each,” notes Behm.1 “Who stretches just their calves for 30 minutes?”
What about shorter stretches?
“When we looked at 125 different studies, we found impairments of about 3 to 5 percent if a single muscle was stretched for more than a minute,” says Behm.2
But that doesn’t mean much for your average weekend warrior.
“Let’s say you usually hit a tennis ball at 100 miles per hour,” says Behm. “If you over-stretch beforehand, you may hit it at 95 mph. What difference does that make to your game? None. A 5 percent impairment may matter for Roger Federer, but it’s trivial for the average person.”
In fact, stretching has a payoff if it’s done right. “If you stretch a muscle for less than 60 seconds, you’re not going to have issues,” says Behm. “And it may decrease the chance of acute injuries like muscle strains without impairing your performance.”2 His advice:
- Warm-up. “Do five minutes or so of aerobic activity like cycling or brisk walking to warm up the body.”
- Static stretching. “Hold each stretch for no more than a minute total.”
- Dynamic stretching. “You could kick each leg back and forth, do big arm circles, that kind of thing.”
- Specific movements. “Do a few minutes of the movements specific to the sport, like hitting a tennis ball a few times, before you start your match.”3
Sports or no sports, stretching has other benefits, like increasing joint mobility. Think of it as its own activity…one you can do, say, while watching TV.
“Improving your flexibility through stretching can make day-to-day activities easier, especially as we age,” says Behm.
“It’s easier to bend over to pick things up. Or maybe you’re hiking and need a longer stride to go uphill or take a large step to get over a rock. If you don’t have that flexibility, you won’t be able to do it.”
The Bottom Line: Stretch before you exercise...and whenever you can during the day.
Lift weights while losing weight?
When you lose weight, you may also lose bone. And that can spell trouble, especially for older adults, whose bones become more fragile with age.
Solution: “Exercise can minimize weight-loss-induced bone loss,” says Dennis Villareal, a physician at the Michael E. DeBakey Veterans Affairs Medical Center in Houston.
Villareal and his colleagues randomly assigned 107 older adults with obesity to one of four groups:
- a diet group that cut 500 to 750 calories a day,
- an exercise group that did balance, flexibility, aerobic, and strength training three times a week,
- a diet + exercise group that did both, or
- a control group that didn’t change their diet or exercise.4
After a year, both groups of dieters had lost close to 10 percent of their starting weight. (The exercise-only and control groups didn’t lose any weight.)
Compared to the control group, hip bone density dropped only in the diet group. It increased in those who did exercise alone and decreased less in the diet-plus-exercise group.
Which type of exercise best preserves bone?
In a new study, Villareal randomly assigned 160 older adults with obesity to one of four groups.
The control group made no changes. The other three groups cut 500 to 750 calories a day and did one of the following three times a week for six months:
- aerobic exercise like treadmill walking, stair climbing, or cycling,
- strength training using weight-lifting machines, or
- aerobic + strength training.5
“All three of the groups who dieted and exercised lost about 9 percent of their starting weight,” says Villareal.
“But aerobic exercise didn’t prevent weight-loss-induced bone loss, whereas strength training alone or combined with aerobic exercise was equally effective at diminishing bone loss.” Ditto for lessening muscle loss.6
The Bottom Line: “When you diet, do exercise, with an emphasis on strength training,” says Villareal.
Work up an appetite?
“There’s a common misconception that exercise is going to make you eat more at the next meal,” says David Broom, professor in the Centre for Sport, Exercise and Life Sciences at Coventry University in England.
“But in the typical person, exercise suppresses appetite for about an hour or so. And at the next meal, people tend to eat the same amount compared to days when they don’t exercise.”7
Of course, there are exceptions. “We pooled the data from 17 of our studies and found that some people’s appetite will not change or may even increase after they exercise,” notes Broom.8
But only vigorous exercise seems to matter.
In one study, 14 young men walked briskly for an hour or rested quietly on separate days.9
“We saw no difference in appetite, the hunger hormone ghrelin, or calorie intake,” says Broom.
“In our studies, you have to get above about 60 percent of your maximal oxygen uptake for exercise to suppress appetite. That means a fast jog or cycling like you’re in a hurry to get somewhere.”7
But those studies don’t tell us what happens to appetite—and food intake—in response to exercise over the long run.
The answer isn’t clear.
In one study, 35 overweight people or people with obesity exercised hard enough to burn 500 calories a day, five days a week, for 12 weeks.10
On average, the group lost about eight pounds, right on par with the researchers’ predictions.
“But when you look at the range, someone lost 32 pounds and someone else gained four pounds,” Broom notes. “There was tremendous variation in weight loss.”
As for food intake, on one test day near the end of the study, people who had lost the least weight ate roughly 270 calories more—while those who had lost the most weight ate 130 calories less—than they did at the start of the study.
“Over time, many people compensate for exercise by eating more,” says Broom.
The Bottom Line: Exercise may briefly curb your appetite, but there are no guarantees.
Roll with it?
We’ve all been there. We embark on a new workout routine and end up stiff, sore, and out of commission for days.
You can blame micro tears in the muscle fibers, notes Memorial University of Newfoundland’s David Behm.
“They’re caused by doing eccentric muscle contractions or exercise that your body is unaccustomed to,” he explains. (Eccentric contractions occur when a muscle lengthens as it’s stressed. They explain why your thighs may be sore after a long downhill hike.)
“When we get those little tears, our body treats them like an injury and sends in the immune system to repair them,” says Behm. “That leads to inflammation—and soreness—that can last for two or three days, sometimes more.”
Contrary to popular belief, stretching before or after exercise won’t prevent muscle soreness.11
“If you’re already sore and you stretch, the soreness might go away while you’re stretching, and that can feel nice,” says Behm. But don’t expect lasting relief.
What might help?
“Buy a foam roller,” Behm suggests. You can use the dense foam cylinder to massage your muscles.
“Our studies show that rolling on foam after exercise reduces soreness.”12,13
In one study, 20 young men did 10 sets of 10 squats—enough to cause micro tears that should later hurt. Half used a foam roller to massage their thigh and glute muscles for 20 minutes immediately after squatting and again 24 and 48 hours later. The foam-rollers reported less soreness than those who did nothing.12
Less pain wasn’t the only upside. “Intense exercise that results in micro tears impairs range of motion, speed, and force, but foam rolling mitigates all those impairments,” says Behm.
And that may enable you to get back to your workout more quickly.
The Bottom Line: Try foam rolling to reduce muscle soreness.
Back me up?
“People often think of low-back pain as not that serious,” says Roger Chou, director of the Pacific Northwest Evidence-based Practice Center at Oregon Health & Science University. “Maybe it hurts, but it’s more of a nuisance than anything.”
But low-back pain has an enormous impact, he notes.
“Globally, it’s one of the leading causes of disability. And in the United States, it’s one of the main reasons why people go to the doctor.”14,15
What causes back pain?
“That’s not a simple question to answer,” says Chou. “Some people have acute back pain maybe due to lifting something too heavy. But often, there’s no specific cause.”
Fortunately, “most people will be back to normal pretty quickly,” adds Chou. But for others, the pain persists.
“Some chronic back pain may be due to arthritis, or maybe the discs between the vertebrae have started to wear out,” says Chou.
But it’s not just what you see on an X-ray. “Mental health, job dissatisfaction, and how people cope with their pain are all linked to the severity and persistence of chronic low-back pain,” he notes.
Compounding the problem: pain can cause people to curtail their movement. “Some people are very afraid of their pain,” says Chou. “They think it means something serious, so they avoid physical activity.”
But movement may help.
“We don’t tell people to lie in bed for three to five days like we used to,” says Chou. “I urge people to try to do their regular activities, to the extent possible, even from the beginning.”
Pain medication is rarely the answer for chronic low-back pain. “Drugs are not going to reduce your pain by much more—or maybe any more—than exercise,” says Chou. “And medications, especially opioids, have side effects.”16
What can best restore your lifestyle and help ease your pain? “Exercise,” says Chou. “And cognitive behavioral therapy, which helps people cope with pain.”
Are you better off with strength training, core stability, aerobic exercise, yoga, or something else?
No one type of exercise stands out.
“The average benefits are all in the same ballpark,” says Chou.17 “That tells me that simply moving is more important than exactly what you’re doing.”
“Many physical therapy programs incorporate a variety of types of exercise and cognitive behavioral principles,” he adds. “They get people to set goals and work through the fear and catastrophizing that may prevent them from getting better. That’s ideal.”
The bad news: exercise only leads to modest relief for chronic low-back pain.
“Chronic pain is really hard to treat,” notes Chou. “On average, we’re talking about an improvement of a point or so on a 10-point pain scale. Some people may improve by more, but it’s not a huge benefit for pain.”
On average, function also improves by only about that much.17
“But we do see some people who have their function almost completely restored, even if they still have some underlying pain,” says Chou.
And just a point or two can make a difference. “We want to get people off the couch, moving, engaging with friends and family, and living their lives again.”
The Bottom Line: “If you have chronic low-back pain, find an exercise that you like,” says Chou. “It’s an opportunity to make some lifestyle changes that are not just good for your back but for all areas of your life.”
1J. Appl. Physiol. 89: 1179, 2000.
2Appl. Physiol. Nutr. Metab. 41: 1, 2016.
3Eur. J. Appl. Physiol. 118: 1427, 2018.
4J. Bone Miner. Res. 26: 2851, 2011.
5J. Bone Miner. Res. 35: 430, 2020.
6N. Engl. J. Med. 376: 1943, 2017.
7Nutrients 10: 1140, 2018.
8Med. Sci. Sports Exerc. 49: 1219, 2017.
9Med. Sci. Sports Exerc. 42: 485, 2010.
10Int. J. Obes. 32: 177, 2008.
11Cochrane Database Syst. Rev. 2011. doi:10.1002/14651858.CD004577.pub3.
12Med. Sci. Sports Exerc. 46: 131, 2014.
13J. Athl. Train. 50: 5, 2015.
14Lancet 388: 1603, 2016.
15Mayo Clin. Proc. 88: 56, 2013.
16Ann. Intern. Med. 166: 480, 2017.
17Ann. Intern. Med. 166: 493, 2017.
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