How Long Should I Exercise?

The length of an exercise session is one of the factors considered when a program is developed.  The goal of any exercise session is to create a change in the body. The workout needs to be long enough to stimulate the adaptation but not so long that affects your ability to recover before the next workout. Unless you are preparing for a long distance endurance sport, the total amount of exercise that you perform during the week is more important than the amount that you do in one session.  In other words four 60 minute sessions are just as good, or better than two 120 minute sessions. There is even a growing amount of research that shows that for improving health many 10-15 minute exercise sessions each week can be just as effective as fewer longer sessions.  The amount of time that you need to spend in each exercise session will depend on your goals, exercise history, and availability.

Even though you may have two hours for exercise that does not mean you should be using the whole time. Exercise science and medical researchers have determined the optimal amount of time or work, for different types of exercise, to make the body improve. Going beyond these levels does not help you improve any faster it only increases the amount of time you need to recover between sessions.


The optimal amount of work for flexibility exercise seems to be about 60s of stretch time per muscle group.  Unless you have specific instructions from a doctor or therapist, the maximum amount of time that it would take to do a full body flexibility session would be about 20-30 minutes. Longer periods of stretching may increase flexibility a little faster but they may also create instability in your joints and have a negative impact on strength exercises.  In the majority of cases 10-15 minutes of stretching daily yields the best results.

While there are many yoga classes that last longer than 30 minutes, there is more than just stretching going on in a yoga class. Breathing exercises, meditation, and strength endurance work are all part of many styles of yoga.

Strength Exercises

Many books and magazines suggest that 48 hours is needed between strength workouts. This is a very general guideline that does not take into account the type of strength exercises, the intensity or the volume. Intensity is the amount of weight or resistance that is being used, usually expressed as a percentage of the maximum you could lift. Volume is the total number of repetitions, calculated by multiplying the number of sets by the number of repetitions per set.  To increase or maintain muscle mass the optimal number of repetitions per body part is 160-200 per week at an intensity of 75-85% of max. To improve strength the range is 75-120 repetitions at an intensity of 85% of max or higher.  This volume of work can be accomplished either through 2-3 longer sessions per week, up to 90 minutes at a time or through 4-6 shorter sessions of 30-45 minutes at a time. There are advantages and disadvantages to both scenarios. If you do not have a lot of time in each session you will have to exercise more often and you will have fewer exercise options in your program because there just is not enough time to have a wider variety of exercises. If you do longer sessions you may be able to do more exercises but you are also more likely to have some muscle soreness after the workout because of the higher amount of work. A quick strength maintenance circuit can be done in as little as 20 minutes 3-4 times per week.

Aerobic Endurance Exercise

As mentioned above aerobic endurance can be built in short 10-15 minute session as long as there are enough of them, 3-4 per day.  Better results will come with sessions that last 30-45 minutes, three or more times per week. If you want to try an endurance sport like running or cycling you may need up to 3-4 hour s per session depending on the type of event that you want to do and how well you want to perform.


The duration and frequency of each session will determine how quickly you progress and reach your goals.  Performing 3-4 sessions per week of 60-75 minutes seems to be optimal for developing a balanced level of fitness. Longer sessions 75-120 minutes 3 or more times per week will allow you to maximize development of a specific type of fitness, i.e. Strength, endurance or flexibility.  Shorter sessions, less than 45 minutes, will still improve fitness but it will take longer to see results and you have fewer options when a program is designed.

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