Although many people view exercise as a way to lose weight, it plays a key role in the wellbeing of the body beyond weight loss. Research strongly supports its benefits across a range of physical and mental health conditions for people of all ages. However, busy lifestyles and an environment that encourages being sedentary for many hours of the day (driving door-to-door, sitting at an office desk, relaxing for the evening in front of a television) have led to exercise ranking low as a priority for many people.
Types of Exercise
All types of exercises offer health benefits. Performing different types of exercises can expand the range of benefits even further. But it is important to remember that some exercise is better than none, and that most everyone can participate in some form of exercise safely.
Aerobic/Cardiovascular physical activity. These are activities that are intense enough and performed long enough to maintain or improve one’s heart and lung fitness. Examples: walking, jogging, dancing, bicycling, basketball, soccer, swimming
Muscle-strengthening activity. This may be referred to as resistance training. These activities maintain or increase muscle strength, endurance, and power. Examples: weight machines, free weights, resistance elastic bands, Pilates, daily activities of living (lifting children, carrying groceries or laundry, climbing stairs)
Flexibility training. This may be referred to as stretching. It lengthens or flexes a skeletal muscle to the point of tension, and holds for several seconds to increase elasticity and range of motion around a joint. Improving flexibility can enhance the overall physical performance of other types of exercise. Examples: dynamic stretches performed with movement (yoga, tai chi), static stretches without movement (holding a pose for several seconds or longer), passive stretching (using an external force like a strap or wall to hold an elongated pose), and active stretching (holding a pose without an external force)
Balance training. These activities are intended to throw off one’s balance to improve body control and stability. They can help to prevent falls and other injuries. Examples: standing on one foot, walking heel-to-toe in a perfectly straight line, standing on a balance or wobble board
Measures of Exercise Intensity
Although just moving more and sitting less offers health benefits, how much energy you use while exercising can increase those health benefits further. This is referred to as energy intensity.
The Borg Scale of Perceived Exertion measures your exercise intensity by rating how you feel. It is based on observations like higher heart rate, heavier and faster breathing, increased sweating, and muscles feeling tired. It does not use actual measurements of these occurrences but a personal self-check.
The scale uses numbers from 6 to 20. The lowest rating is “no feeling of exertion,” at number 6, and the highest rating is “very, very hard,” at number 20. Moderate activities register 11 to 14 (“fairly light” to “somewhat hard”) while vigorous activities usually rate 15 or higher (“hard” to “very, very hard”). Dr. Gunnar Borg, who created the scale, set it to run from 6 to 20 as a simple way to estimate heart rate—multiplying the Borg score by 10 gives an approximate heart rate for a particular level of activity. 
The Borg Scale of Perceived Exertion
|How you might describe your exertion||Borg rating of your exertion||Examples
(for most adults <65 years old)
|None||6||Reading a book, watching television|
|Very, very light||7 to 8||Tying shoes|
|Very light||9 to 10||Chores like folding clothes that seem to take little effort|
|Fairly light||11 to 12||Walking through the grocery store or other activities that require some effort but not enough to speed up your breathing|
|Somewhat hard||13 to 14||Brisk walking or other activities that require moderate effort and speed your heart rate and breathing but don’t make you out of breath|
|Hard||15 to 16||Bicycling, swimming, or other activities that take vigorous effort and get the heart pounding and make breathing very fast|
|Very hard||17 to 18||The highest level of activity you can sustain|
|Very, very hard||19 to 20||A finishing kick in a race or other burst of activity that you can’t maintain for long|
Exercise workouts may vary in intensity throughout the session. You can use the Borg Scale to change the intensity, by speeding up or slowing down movements or applying more or less resistance (such as increasing the incline on a treadmill or turning the resistance control knob on a stationary bicycle).
Target Heart Rate
Calculating your heart rate and target heart rate can be used to measure exercise intensity. First determine your maximum heart rate: subtract your age from 220 (example: the maximum heart rate for a 40-year-old person would be 220 – 40 = 180 beats per minute). The target heart rate for moderate-intensity exercise is between 65-75% of your maximum heart rate (or 77-93% of maximum heart rate for vigorous exercise). So for the 40-year-old person with a maximum heart rate of 180, the target heart rate falls somewhere between 117-135 beats per minute for moderate exercise, or 139-167 for vigorous exercise.
Then measure your actual heart rate in either of these two ways:
- Midway through the exercise, stop to check your pulse. Place the tips of your index and middle fingers at the wrist and press lightly on the artery in line with the thumb. Count the heartbeats for 30 seconds and multiply by 2.
- Wear a heart rate monitor. Some pedometers have a built-in heart rate monitor that displays your current heartbeats per minute.
MET stands for the metabolic equivalent of task. One MET is the amount of energy used while sitting quietly. Physical activities may be rated using METs to indicate their intensity. For example, reading may use about 1.3 METs while running may use 8-9 METs. METs can also be translated into light, moderate, and vigorous intensities of exercise.
- Sedentary—Uses 1.5 or fewer METs. Examples are sitting, reclining, or lying down.
- Light intensity—Uses from 1.6-3.0 METs. Examples are walking at a leisurely pace or standing in line at the store.
- Moderate intensity—Uses from 3.0-6.0 METs. Examples are walking briskly, vacuuming, or raking leaves.
- Vigorous intensity—Uses from 6.0+ METs. Examples are walking very quickly, running, taking an aerobics class, or shoveling snow.
More on METs
Exercise experts measure activity in metabolic equivalents, or METs. One MET is defined as the energy it takes to sit quietly. For the average adult, this is about one calorie per every 2.2 pounds of body weight per hour; someone who weighs 160 pounds would burn approximately 70 calories an hour while sitting or sleeping.
Moderate-intensity activities are those that get you moving fast enough or strenuously enough to burn off three to six times as much energy per minute as you do when you are sitting quietly, or exercises that clock in at 3 to 6 METs. Vigorous-intensity activities burn more than 6 METs.
One limitation to this way of measuring exercise intensity is that it does not consider the fact that some people have a higher level of fitness than others. Thus, walking at 3 to 4 miles-per-hour is considered to require 4 METs and to be a moderate-intensity activity, regardless of who is doing the activity—a young marathon runner or a 90-year-old grandmother. As you might imagine, a brisk walk would likely be an easy activity for the marathon runner, but a very hard activity for the grandmother.
This table gives examples of light-, moderate-, and vigorous-intensity activity for healthy adults:
|Light (1.6-3.0 METs)||Moderate (3.0-6.0 METs)||Vigorous (6.0+ METs)|
Physical Activity Through the Life Course
In the U.S., the Department of Health and Human Services provides specific guidelines for physical activity for different life stages and conditions: 
- Children ages 3 through 5. Try to be physically active throughout the day. Adult caregivers should encourage children this age to engage in active playing for at least 3 hours daily.
- Children and adolescents ages 6 through 17. At least 1 hour daily of moderate-to-vigorous activity with both aerobic and strength movements.
- Adults. Move more frequently throughout the day and sit less. Engage in at least 150 to 300 minutes weekly (spaced throughout the week) of moderate-intensity aerobic exercise and at least 2 days weekly of muscle-strengthening exercises. Greater health benefits may be seen with more than 300 minutes weekly of exercise.
- Older adults. Follow similar activity guidelines as those for adults but also include a focus on balance training. Although discussing the start of a new exercise regimen with one’s doctor is a good practice for all ages, it is especially important with this age group because of the higher likelihood of having health conditions or physical limitations that may require modified exercises. See additional physical activity considerations for older adults.
- Women who are pregnant or postpartum. Aim for 150 minutes weekly (spaced throughout the week) of moderate-intensity aerobic exercise. If vigorous exercise was performed regularly prior to pregnancy, one may continue this throughout pregnancy after discussing with their doctor. See additional physical activity considerations for pregnancy.
- Adults with physical disabilities and chronic conditions. Follow similar activity guidelines as those for adults if able to exercise, but discuss with one’s doctor about the types and amounts of activity that would be appropriate for specific conditions. Any exercises within one’s ability is encouraged, to avoid being completely sedentary. See additional physical activity considerations for chronic conditions.
The frequency, duration, and intensity of exercise are helpful terms to consider when deciding on an exercise regimen.
- Frequency: How often will you do the activity—once a day, three times a week, twice a month?
- Duration: How long is the exercise session—20 minutes, 1 hour, 30 minutes split into two sessions in one day?
- Intensity: How much energy is needed—light versus vigorous activity, 3 METs versus 6 METs?
Wearable trackers for physical activity
Generally these trackers are pretty accurate when measuring steps taken. But other measures, such as how many calories are burned, can overestimate or underestimate the actual amount. Studies looking at the accuracy of devices in tracking calories used while exercising tend to be small in size. In one study, 14 participants wearing different popular brand devices walked and ran. The estimated calorie usage displayed on the devices was compared with measurements from indirect calorimetry (a reliably accurate technique to measure calorie output). The results were mixed. Some of the devices were accurate for calorie expenditure with running but not walking and visa versa. Some of the devices overestimated the amount of calories used during exercise.  Other studies found similar discrepancies. 
Tracking devices can be useful for personal motivation and accountability, but the data should be interpreted with caution as there are variable readings among devices. The accuracy of the data may also vary within the same device when performing different intensities of exercise.  They are best used with other methods to gauge fitness levels, such as monitoring the frequency, duration, and perceived exertion of your exercise routine. It’s also important to have motivation to exercise because you enjoy how you feel during and after the exercise, not just to reach a certain number on a tracker.
Safety should be a major priority when exercising. Any physical activity carries the risk of injury, whether you are just starting an exercise regimen or are a seasoned fitness buff. But don’t let this stop you from moving because the health benefits of being active far outweigh any risks. Using caution and patience can reduce the risk of injuries.
Common workout injuries include:
- Strained or pulled muscles
- Ankle sprain
- Knee strain
- Inflamed tendons or ligaments
- Rotator cuff (shoulder) injury
- Overuse injuries caused by repetitive movements using mainly one part of the body
In very rare cases, vigorous physical activity may lead to a heart attack or sudden death. Active people have a lower risk of serious or fatal heart problems than inactive people.
Not talking with your doctor first. If you are new to exercise or have medical conditions, let your doctor know what type of exercise you’ll be starting. They can review the format to ensure it is safe with a specific health condition.
Doing too much too soon. This is very common as people may be highly motivated when starting a new exercise program. However, forcing your body to move with too much intensity can be jarring to the heart, muscles, and joints that may lack strength from inactivity. This often leads to injury. Even if starting slowly feels too easy, plan to progress exercise gradually. Start with light to moderate-intensity movements for a shorter amount of time, and continue this for a few weeks. As you develop strength and stamina, you can add minutes and higher-intensity movements every few weeks.
Leaving out the warm-up and cool-down. A warm-up before exercising includes light movements that initiate the flow of blood and loosening of muscles and joints. An example would be 5-10 minutes of marching in place, doing arm circles, and neck rolls. After exercising, the cool-down is important to slow down the body and heart rate steadily, as a sudden stop in movements can interfere with blood flow to the brain and cause lightheadedness or dizziness. A cool-down could be simply slowing the pace of whatever exercise being performed for 10 minutes (if jogging, change to a walk; if on a stationary bicycle, release any tension on the resistance knob and peddle slower). The cool-down period may also include stretches that are most effective when the muscles are warmed from exercising; stretches help to lengthen muscles that will protect against injuries. A cool-down with stretching can also lessen muscle soreness the following day.
How to get started safely
- If you have a chronic health condition or are pregnant, let your doctor know of your desire to start exercising.
- If you are sedentary, start with activities that are lower impact and require a light-to-moderate effort, such as walking, gardening, stationary bicycling, or swimming. Progress gradually—it’s especially important to “start low and go slow.”
- Protect yourself:
- Choose the right equipment. If you’re cycling, wear a bike helmet. If you’re going out for a walk, pull on a well-fitting pair of sneakers instead of a pair of flip flops. Generally, exercise shoes should be replaced very 4-6 months as the cushioning wears out.
- Find a safe place to work out. Seek out streets that have sidewalks or bicycle lanes, or visit a local park. Play basketball on well-maintained courts.
- Pay attention to the weather. In the middle of a heat wave, exercise in the morning or evening when it’s cooler out, exercise indoors, or hit the swimming pool instead of the tennis court. Be aware of signs of overheating like dizziness, nausea, headache, cramping, and a racing heart rate that doesn’t slow down even when stopping the exercise.
- Stay hydrated with water. The amount will vary depending on the temperature (more is needed in very hot and humid conditions) and level of exercise. For moderate workouts of one hour or less, bring about 24 ounces of water to drink during and after exercising.
- Choose healthy “fuel.” A diet with adequate amounts of healthy protein and carbohydrates is sufficient to fuel the body for low to moderate amounts of physical activity, such as an hour of jogging or bicycling.
- Be wary of supplement claims. Fitness gurus and advertisements touting workout supplements as crucial for peak performance, fat loss, and explosive muscle growth might have you believing you can’t effectively exercise without them. Although some supplements have been researched for use in regular high-intensity, strenuous physical activity (such as marathon training or power lifting), it’s important to note they are not regulated for safety. Be sure to consult with a doctor before incorporating them into your exercise routine and discuss if there are any potential contraindications if you have existing medical conditions. Learn more about the research on common workout supplements.
- Listen to your body. If you feel very fatigued, pain, or lightheaded while exercising, slow down the workout or end it early.
What’s the difference between muscle pain and muscle soreness?
On the other hand, sharp pain in a specific area that starts during the workout or soon after could be a sign of a more serious injury. See a doctor if the pain does not lessen in a day or two or you notice swelling or bruising around the painful area.
10 Tips to Keep Moving
- Plan exercise into your day. Intention is an important first step. Set aside a specific time in your schedule to exercise and write it in your planner.
- Accountability helps. If your motivation is lagging, connect with a friend or family member with a similar goal to move more. A workout partner can help keep you on track and motivate you to get out the door.
- Try counting steps. Step-counters or pedometers are an easy, inexpensive way to remind yourself to move. Working up to 10,000 steps per day can be a good general goal. If that seems too intimidating, measure your steps on an average day and increase by 1000 steps every two weeks.
- Keep it brisk. When you walk, make it brisk, since this may help control weight better than walking at a leisurely pace. What is brisk enough? Walk as though you are meeting someone for lunch and you are a little late.
- Turn off the TV, computer, and smart phone. Chances are that if you turn off these devices for an hour or two, you will automatically move more and curb your “sit time.” Fill the time by doing household chores, running errands, playing with the kids, or taking a stroll around your neighborhood.
- Turn sit time into fit time. Try to combine movement with a sedentary activity that you already do. For example, perform squats, marching in place, jumping jacks, push-ups, or sit-ups while watching TV or throughout each commercial. Fidgeting, or its scientific term non-exercise activity thermogenesis (NEAT), also uses extra energy. Studies show that people who are lean incorporate more NEAT movements throughout the day compared with people who are overweight.  This might mean pacing around while talking on the phone, tapping your feet when sitting, drumming your fingers on a desk or your leg, or wiggling your toes. For inspiration on how to move “creactively” wherever you are, check out Activating a Move-Friendly World.
- Move at the office. If you work long shifts or care for a busy family after hours, fitting in a workout can be daunting. So focus on moving at the office even if you have a sedentary desk job. Make climbing stairs and avoiding elevators the norm, park as far from the front office door as possible, set a reminder to get up and walk for 5 minutes each hour (that could add up to 40 minutes in a day!), or follow a short desk exercise video online.
- Split the workout. If you are new to exercise and find a 30-minute session challenging, split it into two 15-minute sessions. The fitness benefit may actually be greater if you can exercise with higher energy and intensity in two shorter bouts, than if you tried to exercise for 30 minutes but slowed down from fatigue towards the end.
- Sign up for a class or a specific event. Check out the fitness class schedule at your local gym, yoga studio, or community center. Some offer virtual classes with a live instructor but which you can do at home. Or sign up for a specific event like a road race or walk-for-charity a few months out; this can help drive you to train regularly the weeks leading up to the event. You may find that having a target date or the structure of a weekly class keeps you consistent.
- Reward yourself. Set short-term goals—then acknowledge and reward yourself when achieving them. Positive affirmations are key to building confidence as you commit to ongoing fitness goals. Treat yourself to new exercise shoes, clothing, or workout gear; a new book; or a massage.
- Physical Activity Considerations for Special Populations
- More Research on Physical Activity
- Walking for Exercise
- HIIT (High Intensity Interval Training)
- Yoga for Exercise
- Borg G.A. Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise. 1982; 14:377-381.
- The U.S. Department of Health and Human Services. Executive Summary: Physical Activity Guidelines for Americans, 2nd https://health.gov/sites/default/files/2019-10/PAG_ExecutiveSummary.pdf Accessed 10/19/20.
- Brickwood KJ, Watson G, O’Brien J, Williams AD. Consumer-based wearable activity trackers increase physical activity participation: systematic review and meta-analysis. JMIR mHealth and uHealth. 2019;7(4):e11819.
- Cadmus-Bertram LA, Marcus BH, Patterson RE, Parker BA, Morey BL. Randomized trial of a Fitbit-based physical activity intervention for women. American journal of preventive medicine. 2015 Sep 1;49(3):414-8.
- Price K, Bird SR, Lythgo N, Raj IS, Wong JY, Lynch C. Validation of the Fitbit One, Garmin Vivofit and Jawbone UP activity tracker in estimation of energy expenditure during treadmill walking and running. Journal of medical engineering & technology. 2017 Apr 3;41(3):208-15.
- Evenson KR, Goto MM, Furberg RD. Systematic review of the validity and reliability of consumer-wearable activity trackers. International Journal of Behavioral Nutrition and Physical Activity. 2015 Dec 1;12(1):159.
- Villablanca PA, Alegria JR, Mookadam F, Holmes Jr DR, Wright RS, Levine JA. Nonexercise activity thermogenesis in obesity management. InMayo Clinic Proceedings 2015 Apr 1 (Vol. 90, No. 4, pp. 509-519). Elsevier.
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