How much exercise do we need each week?

by Edmond Cleeman, MD

The purpose of this question is to help illuminate the scientific based recommendation for how much exercise we need to do every week to achieve health benefits. There is so much information floating around in the media that this message is often lost. Exercise has been shrouded in goals of body image and weight loss to such a degree that many people don’t realize that its primary benefit is improving our health by preventing and treating many chronic diseases.

Here are some of the big benefits of exercise:

• Lower risk of mortality (death)

• Lower risk of heart disease, stroke, high blood pressure

• Lower risk of type 2 diabetes

• Lower risk of several types of cancer,

• Better sleep, including improvements in insomnia and obstructive sleep apnea

• Improved cognition, including memory, attention and processing speed

• Reduced risk of dementia and Alzheimer’s

• Fewer symptoms of depression and anxiety

• Better bone health and balance, with less risk of injury from falls

• Better quality of life and sense of overall well-being

I know it sounds too good to be true. But all these incredible benefits are backed up by strong scientific evidence from many studies. Curating the data from these studies has provided the basis for guidelines on the quantity and intensity of exercise to realize these benefits

The US Physical Activity Guidelines (PAGL)

• Aerobic exercise: A minimum of 150 minutes of moderate intensity aerobic exercise or 75 minutes of vigorous intensity aerobic exercise per week

  • Some examples include: brisk walking, running, cycling, swimming.

• Strength exercise: Recommendation includes muscle-strengthening exercises twice per week. Hitting all major upper and lower extremity muscles. 

Moderate intensity Aerobic exercise

Aerobic (or “cardio”) activity gets your heart rate up. When done at moderate intensity, your heart will beat faster and you’ll breathe harder than normal. Think of it as a medium or moderate amount of effort. Examples of moderate-intensity aerobic activities: brisk walking (at least 2.5 miles per hour) – you can use a smartwatch or cell phone to help track your walking speed, dancing (ballroom or social), gardening, tennis (doubles), or biking at approximately 10 miles per hour

Vigorous intensity Aerobic exercise

Vigorous intensity activities will push your body a little further. They will require a higher amount of effort. Examples of vigorous-intensity aerobic activities may include: hiking uphill, running, swimming laps, tennis (singles), or cycling >14 miles per hour or faster.

Self-check when exercising: Use the “talk test” to find out - Is it moderate or vigorous intensity? 

When you’re being active, just try talking:

• If you’re breathing hard but can still have a conversation easily, it’s moderate intensity activity

• If you can only say a few words before you must take a breath, it’s vigorous intensity activity

What a moderate intensity aerobic weekly program might look like in practice:

If in your daily commute to work you add in a 15-minute brisk walk in the morning going to and then again when returning home at the end of the day. That’s 30 minutes per day. If you do that every day (5 days/week) then voila! You have reached 150 minutes of moderate intensity exercise for the week. Some tips may include parking the car at the far end of the lot and walk to the office or store. Another opportunity is to get off one stop early on the train and walk the distance of the last stop.  What counts as activity can be things you may not realize: such as walking your dog briskly, dancing, gardening, raking leaves, these all add up in the physical activity column for the week.

What a mixed vigorous and moderate intensity aerobic weekly program might look like in practice:

You can mix and match vigorous and moderate activity to reach your weekly goal. Remember that every minute of vigorous activity is equal to 2 minutes of moderate activity. For example, on the weekend you bike for 30 minutes vigorously at a speed of 14MPH (equivalent to 60 min mod activity). Additionally, you briskly climb up the stairs in your apartment or office building for 5 minutes three times per week for an additional 15 minutes of vigorous activity (equivalent to 30 min mod activity). Then you add a moderate intensity 20 minute walk (to the grocery, subway, to the park, on the way to work) three times per week, which is an additional 60 minutes of moderate  intensity activity.  Add that up and you have met your weekly requirement.  As you build up stamina you will add more activity every week and gain even more health benefits.

Tips for starting aerobic exercise:

Tip #1: Some people don’t start because they don’t see themselves as an “exerciser.” We may need to reframe that terminology from exercise to physical activity. Everyone can imagine themselves as being an active person and it doesn’t come with some of the preconceived notions or hesitations of exercising. If you have not exercised and this is new, you should start slowly and at a light intensity. You want to avoid an injury and avoid over taxing your body that is not used to exercise. Start simply with walking at a slow pace and build up gradually. Your body and heart need to get accustomed to exertion. Bonus is that walking is free, easy and can be done just about anywhere. No gym membership required.

Tip #2: Exercise is not an all or nothing proposition. This is where people get tripped up and give up before they even start. Science shows that performing less than the PAGL still provides health benefits. For people transitioning from complete inactivity to some exercise it’s fine to do just a little bit, even below the recommended amount. The great news is that even small amounts of exercise can provide significant health benefits in this group of beginners.

Tip #3: Exercise does not require significant chunks of time commitment. People are busy and may feel that they don’t have a 30 minute block of time to dedicate to exercise everyday. This is another hazard where people get tripped up and give up before they even start. The good news is that any amount of activity is better than none. You can break it up into short bouts of activity throughout the day, 5-10 minute increments are ok and provide health benefits.

Tip #4: Don’t get sucked into the body image trap. Avoid the pitfall of associating exercise with body shape and weight loss. Body image and weight loss are difficult to achieve, and many people become discouraged and give up. This makes it difficult for many to initiate or maintain physical activity. Let’s refocus goals to align with our mission that exercise is a powerful tool to achieve better health. Your primary mission is to become and stay physically active. These health benefits start almost immediately even if you don’t see them!

Is exercise safe?

Occasionally physically inactive people worry if it’s safe to exercise. The good news is that scientific studies show that exercise is safe and reduces risk of death and heart disease. But for those who have never exercised before, don’t start with high exertion activity like shoveling snow or running. These high intensity activities can put too much strain on the cardiovascular system in a person not used to being active. Therefore, if you're just starting, take it easy with light intensity activity like walking and slowly build up. Additionally, if you have a medical condition or disability you should consult with your physician prior to starting an exercise routine.  If you have an orthopedic issue that is holding you back from starting, a great option is working with a physical therapist who can help guide you from physical inactivity to being active while addressing these conditions. Even people with arthritis can find exercises that avoid or minimize discomfort.

Strength Exercises

The recommendation for strength (resistance) training is at least two sessions per week. Like aerobic exercise it reduces the risk of some chronic diseases, improves quality of life, and improves physical function, as well as other benefits. Strength is important to maintain the ability to perform activities of daily living, especially in older people, like lifting groceries or climbing a flight of stairs.

Strength training is often more complicated for people to get started. Lack of knowledge on what exercises to perform, how to do them correctly, and potential need for equipment are all obstacles. But you can start with no equipment; simple body weight exercises like push-ups, air-squats, abdominal and core exercises. You can progress to add resistance with minimal equipment like resistance bands, or a light pair of dumbbells or household items. However, many people will progress beyond these, which again makes this more challenging to get right.

Alternatively, you can purchase some exercise equipment such as adjustable dumbbells that allow you to add more weight and take up limited space. You can purchase a pullup bar that fits in a doorway, and a simple exercise bench. 

Another alternative is to join a local gym or “Y” and work with a fitness professional such as a personal trainer to help get you started and motivated. I’ve worked with amazing and very talented trainers that can guide and challenge people to meet their unique needs.

The resistance exercises should be challenging. A simple and easy guideline is the weight should be set so that you can perform 8-10 reps. If you can easily do 20 reps, then the weight is too light, and you should consider increasing the weight. Conversely, if you can only do 2 reps, then the weight is too heavy, and you don’t want to hurt yourself. You should reduce the weight to fall back into this range of 8-10 reps.

You will get stronger and then you should progress the weight to maintain the challenge over time as strength increases. Don’t stay at the same weight as you get stronger, increase the resistance (weight). For example, you start with 10 lb dumbbells for chest presses and do 10 reps, after 3 weeks you can do 15 reps, then it's time to increase the weight to maybe 15lbs. Include all major muscle groups in the upper and lower body, including chest, shoulders, back, hips, and legs. After exercise it’s natural to feel soreness in your muscles. That’s a good feeling, it’s normal, it means your muscles were challenged, are recovering and getting stronger.

If you have an orthopedic issue that is preventing you from being physically active, make an appointment with Dr Edmond Cleeman.