Exercise Intensity and Adherence – What’s Best for Beginners?

Physical inactivity is one of the most challenging health problems in industrialised countries. Over 20 years ago the WHO warned that a sedentary lifestyle was a leading cause of death and disability.

Unfortunately, these warnings haven’t resulted in us becoming more physically active. The 2020/21 New Zealand Health Survey tells us that:

• 47% of adults didn’t accumulate enough weekly activity to be considered ‘physically active’, an increase from 2010/11.

If you think that 47% isn’t that bad, think again. This is based on adults accumulating at least 2.5 hours of physical activity over a week (21 minutes per day). Our National Guidelines actually recommend twice this amount of activity for health benefits such as:

• ‘Better fitness’ (albeit a very ambiguous term from the ‘National Guidelines’)
• ‘Reduced risk of some cancers’
• ‘Maintenance of a healthy weight’.

As a population, we aren’t nearly as active as we should be.

One of the most disconcerting aspects of the problem is what Rod Dishman [ref 1] refers to as ‘the revolving door phenomenon’:

• Approximately 50% of those who initiate a program of physical activity drop out within the first few months.

The ‘revolving door’ challenge can be seen in fitness clubs where heavy investments (time and money) are required to continuously find new members to replace those that drop out.

To a degree, finding new members will always be important. However, rather than just accepting drop out we need to concentrate on dramatically reducing it. We can do this by helping beginner exercisers build an exercise habit, improve their health and fitness, and become advocates promoting the benefits of fitness to their friends, family, and peers.

The better we are at helping beginners, the less we need to do to promote our services – happy clients stay, and happy clients promote for us.

In this article we look at the relationship between exercise intensity and adherence as it relates to beginners. We examine:

• The characteristics of ‘beginner exercisers’
• Why fitness professionals and clubs struggle with beginners
• The exercise intensities best suited to beginners
• Under what circumstances high-intensity training is suitable for beginners.

Who is the ‘beginner exerciser’?

A significant chunk of our Personal Training programme is spent developing an understanding of exactly who our clients are. We classify clients as either: low tolerance (beginners), habitual, or compliant exercisers.

When compared to habitual or compliant exercisers, beginners:

• Don’t have an established exercise behaviour/habit
• Have limited physical capacity to tolerate moderate-high intensity exercise without:
  • Experiencing significant discomfort and fatigue during exercise
  • Experiencing soreness and discomfort for a day or more afterward
• Don’t have strong social connections with fitness staff and/or other club members.

In Exercise Behaviour is More Important Than Working Out we talked about building exercise behaviours and social support structures for beginners. We didn’t cover many specifics with regard to exercise though.

Based on the previous classification, when prescribing exercise for beginners, we advise that exercise should:

• Not cause pain or significant discomfort during, and in the day(s) after
• Not result in feelings of confusion, embarrassment, hassle, or failure
• Enable clients to develop a sense of mastery and a feeling that progress in being made.

Unfortunately, all too often beginner exercisers complain that:

• Their programme is too long or too hard
• They hurt too much during, or in the days after completing their programme
• They look/feel foolish when completing their exercises.

While we’re working hard to train fitness professionals to prescribe appropriately for beginners, as a collective, there’s still significant room for improvement.

Why do we struggle with beginners?

Unfortunately, a disconnect exists in the fitness world.

Beginners, who haven’t built an exercise habit and have a low tolerance for moderate-high intensity exercise, have few positive recent experiences with exercise. Those beginners rely on receiving help and understanding from fitness professionals who typically:

• Love exercise and physical activity
• Have built an exercise habit so long ago that they can’t remember being inactive
• Perceive the discomfort of exercise positively – as progress towards an improved state
• Associate with others who admire, reward, support and encourage physical activity.

Do you see the problem? We’re effectively living in different cultures and talking different languages to those we’re aiming to help.

In my early days as a trainer, I pushed my clients to train hard – we needed to burn as many calories or stimulate as much muscle as possible in a short period of time. I’d regularly prescribe walking lunges; an exercise guaranteed to be ‘felt’ both during and after. Personally, I loved that feeling of delayed muscles soreness through my legs, sometimes up to three days after a session!

What other exercises provide as much ‘bang for your buck’ as the walking lunge?

I wanted beginners to share what I perceived to be great value. If I felt my legs rebuilding and getting stronger, then others would feel the same, and interpret those feelings in the same way…right?

Wrong!

I didn’t become aware of the problem until a client called the gym I worked at. They wanted to know if their ‘injury’ was bad enough to warrant a doctor’s visit. It turns out they perceived the delayed onset muscle soreness (DOMS) differently to me; it was causing considerable distress and discomfort every time they tried to sit down or stand up!

In fitness, we struggle with empathy

Currently, empathy is a fashionable term. It is also completely misunderstood – a point we discuss in detail in our Weight Management programme.

Rather than just looking concerned when the time is right, empathy is actually about developing a deep understanding of the feelings/experiences of other people. As the saying goes – it’s about attempting to walk a mile in another person’s shoes.

If I had empathised with my beginner client in the earlier example, I would have realised that:

• Their muscular system was completely unprepared for walking lunges (essentially single leg squats with full body weight, repeated multiple times)
• Extreme muscle soreness would logically be perceived negatively, as a serious injury
• Most people don’t enjoy pain and discomfort and won’t come back for more of the same
• Clients need to have their individual preferences catered to rather than overlooked.

In my later years a fellow trainer provided a great example of empathy in action.

At the time, he was taking a new PT for a weekly training session as a form of practical mentoring. The new PT was struggling with her first overweight, beginner clients – ‘why don’t they work harder’?

Rather than answer the question, he took the new trainer through a repeat of their previous PT session. Only this time, he made her wear a 20kg weighted vest. At the end of the session, he asked how she found it. ‘That was the hardest session I’ve ever done’! ‘Well, that was the same session you did last week, only this time you were carrying an extra 20kg. Try wearing that vest for the rest of the day and then answer your own question’.

As fitness professionals, we need to get out of our own heads more often in order to empathise with people who are typically very different to us.

What’s the relationship between exercise intensity and adherence for beginners?

When it comes to intensity and adherence, the relationship isn’t as clear cut as we once thought!

Earlier research (i.e., 20 years ago) tended to favour moderate as opposed to higher intensity exercise for beginners. For example, Perri et al [ref 2] studied 379 sedentary adults assigned to groups participating in walking exercise of either moderate or high intensity.

Moderate intensity was deemed 45-55% of maximum heart rate (max HR) with high intensity 65-75% of max HR. After six months of monitoring:

• Significantly higher numbers of injuries were reported in the higher intensity group
• Greater adherence was observed in the moderate intensity group.

In a 2008 study of 30 young, sedentary adults, Ekkekakis et al [ref 3] confirmed what was believed to be a causal link between intensity, pleasure, and adherence. After exposing the subjects to 15-minute treadmill sessions at, above, or below ventilatory threshold (VT) they found that:

• Exercise intensities exceeding VT were associated with a significant decrease in pleasure.

*NB. Ventilatory threshold refers to an intensity where the oxygen delivery to muscles becomes a limiting factor. The body is forced to rely more on its anaerobic energy system – exercise is perceived to be much harder.

The authors concluded that exceeding VT could negatively impact exercise adherence.

However, such studies represent a problem in this area. When sample sizes are so small (30 people), and exercise is limited to one modality (treadmill) then we need to be wary of reading too much into the conclusions.

Do such findings actually extend beyond young adults and treadmill-based exercise?

High-intensity exercise might be suitable for beginners

In 2014, Heinrich et al [ref 4] compared moderate to high-intensity training for exercise initiation, enjoyment, adherence, and future intentions. 23 inactive, overweight participants took part in an eight-week trial where they were required to complete three exercise sessions per week.

Participants were randomly assigned to the following groups:

• Moderate-intensity aerobic and resistance training (ART)
• High-intensity functional training (HIFT).

The HIFT group completed CrossFit sessions while the ART group completed a mix of aerobic along with full body resistance exercises at a moderate intensity. At the end of the eight-week trial:

• 18 of the 23 participants (78%) ‘adhered’ (completed 90%+ of the sessions)
• 2 participants dropped out from the ART group, 3 participants from the HIFT group
• HIFT dropouts and AFT participants reported lower exercise enjoyment than HIFT participants
• HIFT participants spent significantly less time exercising, maintained their exercise enjoyment, and expressed stronger intentions to continue training.

In contrast to earlier studies, the authors concluded that high-intensity exercise options were suitable for inactive populations.

Once again, we need to be cautious about inferring too much from a study with only 23 participants. 22% of the participants still dropped out after all. However, the study does suggest that the moderate ‘take it easy’ default isn’t always the best option for beginners.

If this is the case – what is it about higher intensity training that might benefit adherence?

Why might HIT promote exercise adherence in sedentary adults?

A 2016 study [ref 5] asked this very question. Over a period of six weeks, 40 sedentary young adults were required to complete three exercise sessions per week, of either:

• High-intensity interval training (HIT). The sessions consisted of 10 bouts of 1-minute high-intensity intervals followed by 1-minute recovery. The intervals were designed to elicit 90-95% max HR, or
• Moderate-intensity continuous training (MCT). The sessions consisted of a bout of exercise designed to elicit a 70-75% max HR response and lasted 27.5 minutes to equate energy expenditure with the HIIT group.

At the end of each week the participants completed a variety of measures including enjoyment of physical activity, peak HR, and peak power output (PPO).

Figure 1. Mean exercise enjoyment across first six weeks of HIT and MCT. Maximum score is 126

The study found that:

• After four weeks of training, participants began to rate HIT as more enjoyable than MCT. This enjoyment continued to increase until the end of the study
• Differences in enjoyment for HIT over MCT were observed despite HIT being more physically strenuous; HIT elicited a higher workload, HR and RPE (Rating of Perceived Exertion) than MCT
• Changes in workload predicted changes in exercise enjoyment.

Noticing progress and developing a sense of mastery are important for beginners

The last point from the study deserves further explanation. The authors suggest that competency with exercise and the perception of progress are key to enjoyment. They note that the participants weren’t blind to the progress they were making. As they became more comfortable with the HIT exercises, and noticed their workloads increasing, this provided positive feedback which increased their motivation and enjoyment.

This fits with our earlier points that beginners must develop a sense of mastery and a feeling that they’re making progress. Higher-intensity exercise may be more conducive to perceiving progress, and feelings of mastery. However, this is likely to be conditional on a crucial factor – support from fitness staff.

Additionally, a point the authors didn’t pick up on is the reality that ‘MCT’ can be somewhat boring and uncomfortable. 27.5 minutes of continuous walking/jogging becomes tedious and the jarring of repetitive foot-strikes is unpleasant for many. In comparison, the breaks between intervals in HIT allow a degree of recovery.

And in a time-poor world, people may perceive 6-10, 1-minute intervals with breaks to be more tolerable than 30-minutes of continuous activity.

The final word

If you’ve read through to the final word – congratulations. Perhaps you’re looking for a straightforward answer to the question ‘what’s the best exercise intensity for beginners’?

Well, I’m sorry to disappoint – the answer is…it depends entirely on the individual client!

Some beginners will:

• Like the challenge of higher-intensity exercise, others will prefer lower intensity
• Need more support and encouragement to develop a sense of mastery, others won’t
• Enjoy any intensity as long as the exercise takes place in a group, others will be happy reading a magazine while walking slowly on a treadmill.

The only way you can determine what intensity is best suited to a beginner is through a thorough client consultation process. This is a core part of our Personal Training programme where you delve into a clients exercise history, preferences, and goals, and prescribe according to these client specific variables.

Regardless of the initial prescription, intensities need to be monitored consistently and modified to suit beginners. We advocate starting easy with beginners and then adding intensity as a sign of progress. This is much more motivational than starting too hard and having to regress the initial prescription.

And for all beginners, regular support is crucial over their first 12 weeks of training to:

• Refine the prescription
• Address any concerns or explain physiological responses
• Help develop a sense of mastery
• Experience the joy of progress which is key to building an exercise habit.

Unless we all get into the habit of providing such support to beginners, we’re unlikely to see any change in the revolving door phenomenon.

References

1. Dishman. (2001). The problem of exercise adherence: Fighting sloth in nations with market economies. Quest (National Association for Kinesiology in Higher Education), https://doi.org/10.1080/00336297.2001.10491745
2. Perri et al. (2002). Adherence to exercise prescriptions: Effects of prescribing moderate versus higher levels of intensity and frequency. Health Psychology. https://doi.org/10.1037/0278-6133.21.5.452
3. Ekkekakis et al. (2008). The relationship between exercise intensity and affective responses demystified: To crack the 40-year-old nut, replace the 40-year-old nutcracker! Annals of Behavioral Medicine, https://doi.org/10.1007/s12160-008-9025-z
4. Heinrich et al. (2014). High-intensity compared to moderate-intensity training for exercise initiation, enjoyment, adherence, and intentions: an intervention study. BMC Public Health. https://doi.org/10.1186/1471-2458-14-789
5. Heisz et al. (2016). Enjoyment for high-intensity interval exercise increases during the first six weeks of training: Implications for promoting exercise adherence in sedentary adults. PLoS One. https://doi.org/10.1371/journal.pone.0168534