Picture it now – as your Exercise Physiologist, we’ve completed a thorough assessment of your health and medical history; discovered your well-being goals and motivators for change; conducted a movement appraisal and strength testing to find your baseline capacities, and prescribed what we believe to be a pretty decent program covering all bases.

We meet one week later to check on your initial progress hoping to learn of some positive changes. However, you the patient informs us that despite your best intentions, you did not make the time to complete your exercises. Life and other commitments took priority, with physical activity and your new program relegated to the sidelines.

Lack of time is often the greatest barrier to exercise that we encounter with our patients. Off the back of this, wouldn’t it be great to know the minimum time required to dedicate to physical activity that can maintain physical performance.

Now, we are not condoning using ‘lack of time’ as an excuse to prioritising your health by being more physically active. The fact is we all have the same amount of time to utilise – it’s simply a matter of prioritising what’s important to you.

If being able to go shopping and comfortably purchase clothing off the rack is important to you, then I daresay you will make the time to be more physically active to help improve this situation. On the other hand, if it’s not such a big deal, other tasks might be more important.

Having said this, as Exercise Physiologists we too are human, and know that circumstances can change. Having a clear understanding of how much movement is required would be handy knowledge to have for when other commitments do require more attention, be it a work-related project, family commitment, or change to your typical schedule. Part of our role as health professionals is to provide you with the most effective list of exercises for you and your unique situation, which includes being realistic around the time you have available to dedicate to physical activity.

 

Minimum effective dose versus de-training

When we talk about the minimum effective dose of exercise, we’re referring to the minimum amount of exercise required to maintain physical performance. Often the goal of our interventions with patients is to improve physical performance to assist with improving many aspects of physical and mental health. This is where we as practitioners get our biggest thrill, by seeing our patients go from strength to strength.

As discussed above however, there may be times when maintenance of physical capacity is a win. Schedule changes mean exercise compliance cannot be maintained at its normal frequency, and therefore the goal-posts must shift. Rather than risking the negative effects of de-training (significant losses in endurance and strength performance can occur when training cessation extends beyond ~2–4 weeks (1)), let’s discuss the amount of physical activity required to maintain performance and keep decline at bay.

 

Maintaining physical performance for the general population

The following practical application information is derived from a narrative review conducted by Spiering, Mujika and colleagues. To read their full review, click here. Their practical applications cover how to maintain:

• short-term endurance,
• long-term endurance,
• VO2 max (measure of aerobic fitness levels),
• 1 Rep Max strength (the amount of weight you can lift for 1 repetition of a chosen exercise), and
• muscle size in both younger and older adults.

 

To maintain short-term endurance (i.e., maximal bouts of exercise lasting ∼4–8 minutes) in general populations:

• Exercise frequency can be reduced to 2 sessions per week, as long as exercise volume and intensity are maintained; or:
• Exercise volume can be reduced by 66% (as little as 13 minutes per session), as long as exercise frequency and intensity are maintained; or:
• Exercise intensity can be reduced to ∼82–87% of HRmax, as long as exercise frequency and volume are maintained.

In lay terms: My takeaway from this is that to maintain short-term endurance, I can perform 2 x13 minute bouts per week at a target heart rate of 149 – 158bpm as a 37 year old (to calculate your own aged-predicted maximum heart rate click here).

 

To maintain long-term endurance (i.e., maximal bouts of exercise lasting ∼1–3 hours) in general populations:

• The minimal exercise frequency is not known. Therefore, we conservatively recommend maintaining exercise frequency at or near the individual’s typical training level.
• Exercise volume can be reduced by 33% (as little as 26 minutes per session), as long as exercise frequency and intensity are maintained.
• Exercise intensity must be maintained as high as reasonably possible (at least as high as the individual’s typical training intensity).

In lay terms: Due to it’s aerobic demands, maintaining long-term endurance appears to be dictated more substantially by training frequency. If for example you are training for a half-marathon, this may point to the importance of choosing a window of time where distractions and other commitments are less-likely to impact your training opportunities.

 

To maintain VO₂max (what is VO2 max?) in general populations:

• Exercise frequency can be reduced to 2 sessions per week, as long as exercise volume and intensity are maintained; or:
• Exercise volume can be reduced by 66% (as little as 13 minutes per session), as long as exercise frequency and intensity are maintained.
• Exercise intensity must be maintained as high as reasonably possible (at least as high as the individual’s typical training intensity).

In lay terms: My takeaway from this is that to maintain my VO2 max, I can perform 2 x13 minute bouts per week at or as close to my maximal heart rate of 182bpm (as a 37 year old with no contraindications to exercise eg cardiac conditions). This would likely look like circuit or high-intensity interval training, for example combinations of Tabata training protocols.

 

To maintain 1RM strength (what is 1 rep max?) in general populations:

• Exercise frequency can be reduced to 1 session per week;
• Exercise volume can be reduced to 1 set per exercise;
• We conservatively recommend an exercise intensity that results in maximal effort during the final repetition of each set (or maintaining the exercise load at least as high as the individual’s typical training level).

In lay terms: To maintain my 1RM strength for eg a back squat, I can perform 1 session per week of 1 set per exercise at a load where I must work at a maximal effort for the final repetition (if doing this, it’s important to train with a spotter or friend to ensure safety). Think lunges, squat variations and lifting exercises.

 

To maintain muscle size in younger adults (∼20–35 year old) general populations:

• Exercise frequency can be reduced to 1 session per week;
• Exercise volume can be reduced to 1 set per exercise;
• We conservatively recommend an exercise intensity that results in maximal effort during the final repetition of each set (or maintaining the exercise load at least as high as the individual’s typical training level).

 

To maintain muscle size in older adults (∼60–75 year old) general populations:

• We conservatively recommend an exercise frequency of 2 sessions per week;
• We conservatively recommend 2–3 sets per exercise;
• We conservatively recommend an exercise intensity that results in maximal effort during the final repetition of each set (or maintaining the exercise load at least as high as the individual’s typical training level).

In lay terms: The increased recommendations in frequency and volume of exercise compared with younger adults is likely due to a greater de-training effects in older adults, due to endocrine changes and subsequent age-related decline in skeletal muscle mass and bone density.

 

Conclusion

It’s important to remember that these recommendations are relevant when the goal is to maintain physical performance. As stated previously, the vast majority of our patients come to Restart wanting to improve their physical capacity, be it muscle strength, aerobic endurance, bone density or balance. In such circumstances, it is important to exceed the above recommendations for exercise frequency, volume and intensity.

When other life commitments dictate more energy and focus however, the above recommendations can be utilised to preserve precious progress made during previous bouts of exercise. To avoid the negative effects of de-training, which can quickly become apparent when ceasing exercise altogether, setting a target to tick off the above amounts of exercise per week (goal dependent) will allow for maintenance of physical performance whilst you ‘steady the ship’ of life.

Note: before engaging in the above, consult with an Exercise Physiologist to determine the appropriateness of each recommended protocol, especially if you have any history of cardiopulmonary or cardiac conditions. These recommendations are for the general public, and may not be altogether safe should you have any specific health considerations.

Luke

 

Reference

1. Spiering, B.A., Mujika, I., Sharp, M.A., Foulis, S.A. Maintaining physical performance: The minimal dose of exercise needed to preserve endurance and strength over time. Journal of Strength and Conditioning Research 35(5):p 1449-1458, May 2021. | DOI: 10.1519/JSC.0000000000003964