“How often should I exercise?” Here’s what science says.

how often should i exercise

Many of us know we should be exercising, we tell ourselves we’ll get started, and yet still don’t do it. Some of us do end up doing it after a doctor intervenes. I’m no exception!

When I was a first-year undergrad I used to tell myself I’d start going to the gym. Somehow the start date kept getting postponed. Until a year later, I still hadn’t started exercise. That’s when I got knee pain. I could hardly bend my left knee. I had difficulty walking. So I went to the office of an orthopedic doctor to get help.

I was 115 pounds at the time, so extra weight was definitely not the source of my pain. It was summer and I was wearing a no-sleeve top. The doctor first examined my knee. Then he looked at me.

“You’re not exercising, right?”

No,” I said shyly, already feeling guilt for not having already started exercising.

He said something about how he could clearly see that since my shoulder was “just bones.” I don’t remember exactly how he phrased it but his point was that I had no muscles and it showed. (His tone was not derogatory, he was being descriptive.)

And then he went on and prescribed exercise for my knee pain. He said if I worked my quadriceps the pain would go away.

I promptly went on and enrolled at a gym. A doctor’s exercise prescription was the impetus I needed to get it done! And yes, the pain did go away.

Fast forward more than 10 years I’m happily exercising multiple days a week. In a way I’m lucky the doctor intervened at such a young age. What if I had never had that knee issue? Would I still have started exercise or would I have kept postponing it?

If you’re also like me, don’t wait for a doctor to tell you to exercise – do it now. And to adopt a popular saying to exercise: The best time to start exercise was when you were a kid; the second best time is today. Let’s do it.

First, don’t get overwhelmed. These recommendations can be your end goal, not your start goal.

I know these exercise recommendations may sound like a lot, especially if you’re currently not exercising. However, as the American College of Sports Medicine states: “Adults who are unable or unwilling to meet the exercise targets outlined here still can benefit from engaging in amounts of exercise less than recommended.”

Don’t let perfectionism kill your living healthily dream.

When I first started the gym, the trainer told me I had to go 4-5 times a week. I told him “noway.” I had just spent a year postponing exercise; making me go from 0 to 4-5 times a week was just way too much for me at the time.

Instead, I did what I was comfortable with. I was going 2 or sometimes 3 times a week. Was I jealous of people who were exercising 5 days a week? Absolutely. But at the same time, there was no way for me to exercise that often (or so I felt at the time, I’m exercising 5 times a week now!)

Admittedly, going from 2-3 times a week to 5 or 6 times a week (and doing it consistently) has been a personal journey of mine. I even wrote a book about it.

Now, let’s review the terminology.

What is moderate-intensity aerobic activity?

When you’re doing moderate exercise, you can talk but you cannot sing. These activities often count as moderate-intensity:

  • Brisk walking
  • Cycling at pace slower than 10 miles per hour
  • Ballroom dancing
  • Simple gardening (no digging)

What is vigorous-intensity aerobic activity?

When you’re doing vigorous exercise, you can hardly talk without stopping to take a breath. These activities often count as vigorous-intensity:

  • Jogging or running
  • Swimming laps
  • Tennis (singles)
  • Hiking uphill or with a heavy backpack

What counts as a strength-training activity?

Strength training (or resistance training) activities help your muscles get stronger. Activity examples are:

  • Lifting weights
  • Body-weight exercises like push-ups, squats, or sit-ups
  • Using resistance bands

How often should I exercise to be healthy?

Here are the latest general guidelines for healthy adults who want to get the health benefits of exercise. Adults need both aerobic and strength-training exercise.

How much strength-training exercise should I do?

Haskell et all. recommend strength training at least twice a week:

  • You need to work all muscle groups, including legs, back, abs, chest, shoulders and arms.
  • Do one set of 8-12 reps for each exercise.

The American College of Sports Medicine recommends that you don’t just train for strength but also for balance, agility, and coordination.

How much aerobic exercise should I do?

Here’s the current recommendation:

  • 2 hours and 30 minutes each week (total of 150 minutes) of moderate-intensity aerobic activity. That’s the 30 minutes a day Monday through Friday recommendation we’re all so familiar with.
  • Or, 1 hour and 15 minutes (75 minutes) of vigorous-intensity aerobic activity. That’s about 20 minutes of exercise 3-4 times a week.
  • Or, a combination of the above that gives you an equivalent result. For example, you can walk briskly for 30 min twice during the week and then jog for 20 min on two other days.

Aerobic activity should be performed for at least 10 minutes at a time. So 10 minutes of cycling on Monday and 10 minutes of brisk walking on Wednesday and 20 minutes of jogging on Thursday equal 40 min of aerobic activity. Those 10 min slots COUNT.

How much stretching should I do?

I didn’t find any official government guidelines for stretching. However, the American College of Sports Medicine recommends completing a series of flexibility exercises, holding each stretch for 60 seconds, for each of the major muscle-tendon groups twice a week.

The rationale behind stretching is to maintain joint range of movement.

What If I want to be uber-healthy? Do more cardio, says the CDC.

Don’t want to do the minimum recommended, but want to get to the next level? This is what the CDC recommends:

  • 5 hours each week (300 minutes) of moderate-intensity aerobic activity. That’s like an hour a day Monday through Friday.
  • Or, 2 hours and 30 minutes (150 minutes) weekly of vigorous-intensity aerobic activity. That’s like 30 minutes a day Monday through Friday.
  • Or, a mix of the above that gives you an equivalent result.

So say I meet these guidelines: What do I have to gain?

The benefits of exercise are too many to report here, but I’ll do my best to be brief. Assuming you’re a healthy adult with no specific conditions who starts exercising regularly, then most likely:

  • Short-term benefit: You’ll get a sense of accomplishment after each and every workout! Whee!
  • Short-term benefit: Your mood will inevitably get better.
  • Medium-term benefit: The same everyday activities that used to tire you, will now feel easier. Chasing or lifting your kids, running errands, taking stairs, cleaning your house or gardening.
  • Medium-term benefit: You’ll start looking different. I’ve never heard of anyone, ever, complaining about looking more toned!
  • Longer-term benefit: You’ll reduce your risk of dying from cardiovascular diseases by about 30-40%. And that’s just one of the several long-term health benefits.

How often should I exercise to lose weight?

Weight loss depends on how many calories you consume and how many you burn. Exercise helps with the latter while diet helps with the first. For most people it’s easier to consume less than to burn more, but that, of course, depends on personal preferences and on how fast you want to lose the weight. Studies show that doing both (diet and exercise) is the most helpful in losing weight.

Let me be clear here: Fitness has an independent impact on preventing diseases associated with obesity (like coronary heart disease and diabetes.) So just by exercising, even if you don’t lose weight, you will be enjoying at least some of the protective benefits of exercise.

Ok back to the question – how often should you exercise if you want to lose weight?

It depends on what’s sustainable for you. I could tell you to do 5 hours a day. That would definitely be a calorie burner, however, it would not be very sustainable. The last thing you want is to lose some weight and then gain it back, so I strongly recommend you avoid unsustainable jumps and focus on making exercise a habit first.

For people who specifically want to lose weight and were thinking of joining Flat Belly Firm Butt in 16 Minutes, Fitness Reloaded’s total body home workout program where people do high-intensity exercise for 16 minutes 3 times a week, I recommend you add some type of aerobic activity to increase the number of calories burnt.

Walking or cycling for 30 minutes or more another 3 times a week is a good booster. Take this up one level to jogging to cycling faster and you get to burn even more calories.

How often should I exercise if I have a special condition?

The guidelines above provide general recommendations for healthy adults wanting to live a healthy life. But what if you have a medical condition? In this case, exercise for you might be more of a prescription that’ll help you get healthier faster than just a general recommendation for healthy living.

Here’s what Pedersen et al. reported in their 2015 study published in the Scandinavian Journal of Medicine & Science in Sports. Understand that these are generic guidelines for people with specific conditions, they are not custom-tailored to you. Please talk to your doctor before you embrace them.

Pedersen et al. covered 26 conditions but for the sake of brevity I’ve picked 7 “popular” ones to discuss here: Type 1 and type 2 diabetes, coronary heart disease, osteoarthritis, osteoporosis, asthma, and hypertension.

Type 2 Diabetes

Lack of fitness increases your chances of getting a “bad outcome” with type 2 diabetes. Studies show that both aerobic and resistance training are beneficial, so a combination of the two is highly recommended. Also, high-intensity exercise most likely improves glycemic control compared to low-intensity exercise, so raise your heart rate up.

Type 1 Diabetes

People with type 1 diabetes can do all sorts of exercise, however, they have to be careful not to get hypoglycemia and need to frequently measure their blood sugar level, both during and after training. Training with high-intensity exercise stimulates glucose production in the liver so it may be a better choice than moderate exercise.

Physical activity should be postponed in the case of a blood sugar level >17 until it has been corrected. The same applies to low blood sugar <7 mmol/L if the patient is receiving insulin therapy.


High blood pressure increases the risk of stroke, heart attack, and heart failure. It seems that exercise can be just as effective for lowering hypertension as drugs, even if the patient does not lose weight.

All types of training are recommended (endurance, strength training or isometrics), however if your blood pressure is higher than 180/105, then wait till you get started on a drug treatment before you engage with exercise.

Avoid training with very high intensity or with weights that are too heavy, as heavy strength training can create high pressure in the left ventricle of the heart which can be dangerous.

Coronary Heart Disease
People with CHD normally start with a cardiac rehabilitation program. Once they are done, they can usually start with aerobic training 20-60 min, 3-5 times a week at an intensity of 50% to 80%.

Strength training should also be included and the intensity increased as the patient gets stronger and fitter.

Bronchial asthma

Bronchial asthma is a chronic inflammatory disorder of the airways that causes periodic “attacks” of coughing, wheezing, shortness of breath, and chest tightness.

The recommendation to asthmatic individuals who are currently unfit is to start training at low intensity and then gradually increase to moderate. The goal is to exercise 3 days a week or more 1-2 months after the beginning.


Osteoarthritis is a joint disease that’s extremely common. Most people over the age of 60 show signs of the disease on at least one joint. Young people can get it too, mostly due to injury.

Exercise can be extremely helpful to these people. It can help relieve their pain and increase their range of motion. The effect of resistance training in the knee and hip joints can be compared to the effect of anti-inflammatory drugs. The effect of aerobic training on knees osteoarthritis is comparable to corticosteroid injections.

That said, osteoarthritis works differently on different people, so there is no one-size-fits-all advice. Consult with a professional first about whether you should focus first on aerobic capacity, quadriceps strength, or performance.


Most of us have heard about osteoporosis, a disease characterized by a decrease in bone mass density. Osteoporosis patients have a higher risk of bone fracture and falling can be especially dangerous to them.

Both aerobic and strength training have a positive effect on bone mass density. Combine that with balance training and you get an excellent combination to help prevent falls and fractures.

Please make sure that the training itself does not put you at risk of falling.

So how do you go from where you are to meeting the official exercise guidelines?

If you’re not currently exercising and feel totally overwhelmed by reading the recommendations, I suggest you check out Exercise Bliss. It’s made to help people like you become like the people who exercise daily and like it! (I know it may seem like a long shot but it happens!)

If you’re currently exercising, but wish you were doing it more often, I suggest you check out Flat Belly Firm Butt in 16 Minutes. It’s a high-intensity, total body, online home workout program. It combines both cardio and resistance training. If you find yourself aiming to exercise, say 4 times a week, but exercising only 2, then you may want to check it out. Go here to try a free flat belly workout.

I strongly recommend doing what comes more naturally to you. So if you like walking, start with walking around the block. If you’re exercising 1-2 times per week, start by going for twice a week and aiming to be consistent for two months. If you have dumbbells at home, start by doing a couple of exercises a few times per week. You don’t need to start big. You only need to start. I’ve hand-picked both cardio and strength-training exercises for you in my Flat Belly Firm Butt book.

Ok, now time for comments: How much are you exercising right now? Was it easy or difficult for you to get there? Where do you want to go from now on?



William L. Haskell, PhD et al., Physical Activity and Public Health Updated Recommendation for Adults From the American College of Sports Medicine and the American Heart Association. Circulation. 2007;116:1081-1093.

Garber CE et al., American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011 Jul;43(7):1334-59.

CDC, 2008 Physical Activity Guidelines for Americans Fact Sheet for Health Professionals on Physical Activity Guidelines for Adults

B. K. Pedersen et al., Exercise as medicine – evidence for prescribing exercise as therapy in 26 different chronic diseases. Scandinavian Journal of Medicine & Science in Sports. 2015;25:1-72

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  1. I started weightlifting about 2 years ago at age 35 and it was the most consistently I had ever exercised in my life. Unfortunately as I started lifting more I started experiencing intense pain. I was diagnosed with fibromyalgia a few months ago and was told I shouldn’t lift heavy any more. I just started working out again this week with lower weight but higher reps. Feeling a bit lost and confused but hoping I can find a routine that works for me. I had just started incorporating some cardio when I quit due to the pain issues so I’m hoping I can get back to that point of 3-4 days of lifting and 2 of modest cardio, although we have a 2 week old baby that might have something to say about that!

    1. I know, it’s such a bummer to be on a roll and then get slowed down because of health issues! Congrats on the baby! In a few months he/she’ll make sure you do some cardio most days of the week! 🙂

  2. Great article once again Maria! I’ve recently become a freelancer and decided it was time to catch up on my promises to make exercise a regular habit, with a flexible schedule I can’t keep on making excuses. I don’t think I’ve ever been so determined about it, I finally realized that if I don’t do it now, I might never do it later, or at least it’s gonna cost me double the effort – I’m turning 30 and would like to have babies some time in the not so distant future..anyway I realized my circumstances were perfect for cultivating a new habit right now.
    Accordingly, I started running 2-3x a week, something I never did before, and experienced pure bliss. After a couple of weeks though I started having excruciating pain in my lower back and was diagnosed with sacroilitis. I got medication but have had moderate pain on and off ever since. I spoke to several doctors, some said stop running, others said continue. I’m REALLY bummed out because even though I’m careful, I still experience pain the day after my runs, and I cant keep it a regular habit. I tried SO many types of exercises already, swimming, gym, yoga, all sorts of group classes, HIIT, you name it… and this is the FIRST time I feel I’ve found smth I could seriously commit to… but my body won’t let me.. how cynical!
    If you have any suggestions or ideas I would be curious to hear what you think!

    1. Hi Tündi, I’m very happy you found exercise that you really love. Must be a big bummer to get sacroilitis getting in your way now.

      I don’t know why but this reminds me of a break up 🙂 It seems that the feeling is that running is the “one,” however there may be other ways to exercise out there that can be equally satisfying and non-aggravating. In Greece we have a saying we tell our recently broken up friends: “the are other orange trees that bear oranges!”If you and running are able to “get back together” then awesome, but if not be open to the possibility of a new equally effective way to exercise. Don’t know if this helped!

  3. Love your common sense columns. Great advice. I can verify to the power of regular exercise. I do not go to a gym, I workout at home. I turned 60 on August 1st, and work out at least 5 days a week, or more. I walk my dog at least 6 days a week (she insists!), and have a library of cardio and circuit training routines that are 30 minutes each. I started working out about 4-5 years ago, and began with Jane Fonda DVDs for older people 2 or 3 days a week. Not anymore. I track “Fitness Minutes” on the Sparkpeople site and currently have logged 9877 minutes for 2016. Health benefits – no pain anywhere, knees, hips, etc. even doing strength training many days. I have elevated blood pressure controlled with a low dose of one medication. But, even though I am trying to lose weight at about 200 pounds (down from 265!), my cholesterol (HDL – 74), blood sugar, and every other test run was in the normal range. Exercise is a part of my life now..