Trainers love responders. These clients succeed immediately and continue
month after month, losing weight, gaining strength, slicing off inches,
normalizing hypertension, improving cholesterol levels, sleeping better
and feeling better overall.

Then there are nonresponders. They hire trainers, have good intentions,
train regularly and try as hard as they can to improve their health
habits. But they do not lose much weight or fat, nor do they improve
their muscle strength. They may feel better or sleep better, but they
never seem to get the results they are looking for.

Frustrated nonresponders and their trainers need to understand that
there may be a good reason for this lack of progress. It’s possible
these clients have a genetic makeup that resists traditional exercise
programs. Then the question is, if some people are natural-born
nonresponders, is it even possible to turn them into responders?
Multiple research studies suggest the answer is yes—especially if you
add intensity, duration and resistance to their workouts.

Add Some Intensity to the Cardio

One way to help nonresponders is to increase the duration and/or
intensity of the cardio training, according to one recent study.

Ross, de Lannoy & Stotz (2015) investigated whether exercise of
different intensities and durations improved cardiovascular fitness
(cardiorespiratory fitness was measured using a graded exercise test in
which subjects walked on a treadmill). The study had 121 middle-aged
(53.2 years) subjects (75 women, 46 men), all of whom were abdominally
obese. Everybody completed at least 90% of the five weekly workouts over
24 weeks. Subjects were randomly assigned to one of three training

  • low-amount, low-intensity training—30 minutes at 50% of peak VO2,
    designed to burn 180–300 calories per session
  • high-amount, low-intensity training—60 minutes at 50% of peak VO2,
    designed to burn 360–600 calories per session
  • high-amount, high-intensity—40 minutes at 75% of peak VO2 designed to
    burn 360–600 calories per session

After 24 weeks, the researchers tallied the nonresponders in each group.
In the low-amount, low-intensity group, more than one-third (15 of 39)
were nonresponders. In the high-amount, low-intensity group, the
nonresponse rate declined to about one-sixth (9 of 51). Notably, the
high-amount, high-intensity group had zero nonresponders.

The authors suggested that this study provides prescription options for
trainers who work with beginning adult exercisers because it illustrates
the results of adding quantity and intensity to workouts (see Tables 1
and 2 for more on programming for nonresponders).

Interval Training Also Works

Bacon et al. (2013) combined data from several studies to investigate
the effectiveness of adding intervals to continuous exercise. The main
finding was that interval training improves VO2max beyond the gains
reported with continuous cardio training.

The meta-analysis, which evaluated studies that used interval training
either alone or combined with continuous training, found a mean increase
in VO2max of 500 milliliters per minute, compared with 400 mL per minute
in the HERITAGE study described in the sidebar. The analysis also
suggested that longer intervals combined with high-intensity continuous
training can produce increases in VO2max in almost all relatively young

It appears that intervals of 3–5 minutes are especially effective for
improving VO2max. The nine studies that saw the largest increases in
VO2max (~850 mL per minute) generally used intervals of 3–5 minutes with
2-minute rest periods and high-intensity continuous training.

Do We Really Need Cardio?

Given that many nonresponders identified in research studies were doing
long-duration, low-intensity, continuous exercise—that is, cardio—while
interval training and higher-intensity continuous exercise eliminated
nonresponders in some cases, it’s worth asking: Do our clients really
need cardio?

Many clients love cardio because it gives them the best results. These
people thrive on taking long walks, running along the beach or in the
mountains, riding an exercise bike listening to their playlist, running
on a treadmill and getting lost in their thoughts, and/or swimming lap
after lap. However, some clients either don’t respond to cardio or do
not enjoy it (or both).

Nevertheless, many trainers prescribe cardio whether clients like it or
not. Or, perhaps, the clients keep doing it because they think cardio is
the way to maximize results.

Interestingly, when asked if cardio is essential to an exercise program,
many trainers say their clients need it in their program. Yet based on
results from the HERITAGE study, it may be safe to rethink the use of
cardio for so many clients. After all, there is plenty of research and
anecdotal evidence that so-called nontraditional forms of training, or
“metabolic training,” can give clients better results than cardio.

Next up, we’ll review research pointing to viable alternatives to cardio.

Korean Tae Kwon Do for the Elderly

Brudnak, Dundero & Van Hecke (2002) wanted to find out if the “hard”
martial art of Korean tae kwon do could help senior citizens improve
muscle strength, flexibility and balance and thereby reduce falls—a
leading cause of death in this age group.

The researchers found that subjects who attended more than 85% of
classes averaged more push-ups, increased their trunk flexion and
improved their balance time on each foot. Equally important, the dropout
rate was low, suggesting that elderly exercisers are capable of
performing Korean tae kwon do and that it can hold their interest.

Yoga for Obese Teen Boys

Seo et al. (2012) investigated the use of yoga training to improve the
metabolic profiles of obese boys. Twenty obese adolescent boys, all
about 14 years old, performed yoga asana three times per week for 8
weeks at 40%–60% of heart rate reserve (HRR). The boys were tested on
the following metabolic measures: body weight, body mass index, fat
mass, body fat percent, fat-free mass and basal metabolic rate.

After 8 weeks, body weight, body mass index, fat mass and body fat
percent were significantly lower, while fat-free mass and basal
metabolic rate were significantly higher. The authors suggested that
yoga can be an uncomplicated therapy for obese adolescent boys.

Medium-Intensity Intervals

Tremblay, Simoneau & Bouchard (1994) compared the effect of continuous
exercise versus medium-intensity interval training on VO2max, estimated
calories burned, sum of six skinfolds, and muscle enzymes that promote
fat use during exercise. Subjects were aged 18–32. There were two

• Continuous exercise. Eight men and nine women performed a
20-week endurance training program by cycling four, then five, times per
week for 30 minutes, with sessions increasing to 45 minutes toward the
end of program. Intensity was 60% of HRR at the start of training and
had risen to 85% by the end.

• Medium-intensity interval training (MIIT). This technique
produced notably different results from those gained through continuous
exercise, so we will explore MIIT in much greater depth, as it points to
possibilities for nonresponding clients.

In the MIIT protocol, five men and five women started with 25 half-hour
sessions of continuous cycling at 70% of HRR, with half of the training
sessions completed by week 5. After that, they performed 19
short-interval trainings and 16 long-interval trainings over 15 weeks.
The short-interval trainings had 10 bouts of 15-second intervals, later
increasing to 15 bouts of 30-second intervals. The long-interval
trainings had four to five 60-second bouts, increasing to 90-second

The rest interval was determined by noting when heart rate returned to
120–130 beats per minute. Short-interval intensity was 60% of maximal
work output in 10 seconds, while long-interval intensity was 70% of
maximal work output in 90 seconds.

Study results found that VO2max increased with both training programs,
rising 36.6–48.2 mL/kilogram/min for continuous training vs. 38.7–48.6
mL/kg/min for MIIT. Calories burned during the entire study showed that
the continuous exercise group used 28,757.04 kcal, whereas the MIIT
group used 13,829.17 kcal.

The data on skinfold reduction was most intriguing. It showed that even
though the continuous training group burned twice as many calories, the
MIIT group had a much larger reduction in the sum of six skinfolds. The
continuous group reduced its six-skinfold sum from 79.2 millimeters to
74.7 mm, while the MIIT group reduced the same measures from 94.2 mm to
80.3 mm. When the decrease in the skinfolds sum was divided by calories
burned, subcutaneous fat reduction was nine times greater in the MIIT

Muscle enzymes data was also revealing: The MIIT program increased three
of the four enzymes measured, while the continuous program produced no
gains. This showed that the MIIT program boosted the enzymes promoting
fat use to produce energy for muscle contraction, and increased fat use

Weight Training Is the New Cardio

Resistance training is another avenue for turning nonresponders into
responders. In addition to burning calories, resistance helps clients
improve fitness, reduce weight and body fat, increase bone mineral
density and improve self-confidence. Artero et al. (2012) did a review
of literature on the effects of increased muscle strength and found that
it has a protective effect on all-cause and cancer mortality in healthy
middle-aged men, men with hypertension and patients with heart disease.

Increased muscle strength is associated with reductions in weight and
fat, a lower risk of hypertension and decreased prevalence of metabolic
syndrome. After reviewing literature on the benefits of resistance
training, Westcott (2012) reported that they include improvements in
sports and fitness performance, movement control, walking speed (in the
elderly), functional independence (for elderly clients), cognitive
abilities and self-esteem. Moreover, resistance training can promote
bone development, with studies showing a 1%–3% increase in BMD (Westcott
2012). This type of exercise has also been shown to reduce low-back pain
and decrease the discomfort of arthritis and fibromyalgia (Westcott

McGuigan et al. (2009) investigated the effect of resistance training on
overweight or obese children. There were 26 girls and 22 boys (mean age
9.7 years) who weight-trained 3 days per week for 8 weeks. The study
found a 2.6% decrease in body fat, and a significant increase (5.3%) in
lean body mass. Strength improvements included one-repetition maximum
squat (74%), number of push-ups in 1 minute (85%), countermovement jump
height (8%), static jump height (4%) and power output (16%).

Helping Nonresponders: At a Glance

A few key facts about helping people who haven’t responded to your training:

  • Genetics helps explain the wide variance in how peoplerespond to exercise (Bouchard et al. 1999). Because everybody responds differently, trainers have to develop regimens specific to their clients’ needs.
  • High-amount, high-intensity exercise (40 minutes at 75% of peak VO2) produced results for all the people who per- formed it in one study (Ross, de Lannoy & Stotz 2015).
  • Cardio with intervals does more for VO2max than continuous exercise, particularly if the intervals are of longer duration (Bacon et al. 2013).
  • Medium-intensity interval training can produce notable changes in VO2max, a reduction in skinfold measures, and increases in enzymes that help use fat for energy during exercise (Tremblay, Simoneau & Bouchard 1994).
  • Exercise alternatives such as tae kwon do, yoga and weight training may be viable choices for clients who respond poorly to cardio or who do not enjoy it.
Limits of Generalized Guidelines

Many organizations provide general guidelines for improving or maintaining cardiovascular, muscular and neuromotor fitness in healthy adults. Some guidelines suggest 150 minutes per weekof moderately intense exercise, 75 minutes per week of higher-intensity exercise, or a combination of the two (Garber et al. 2011; AHA 2014). Unfortunately, these recommendations are so broad they most likely apply to only a small percentage of our population.

For instance, Ross, de Lannoy & Stotz (2015) found that 150 minutes of low-intensity exercise per week was not enough to improve cardiovascular fitness for 38.5% of their subjects; in contrast, all the subjects improved their fitness in a longer, higher-intensity exercise program. Bouchard et al. (1999) showed that 20 weeks of continuous exercise improved VO2max in some people, while in others VO2max did not improve at all. Likewise, some people who did the same 20-week, 3-days-per week training program saw improvements in their HDL cholesterol while others showed a decline in their “good” cholesterol.

Because all people respond to exercise differently, it is almost impossible to provide guidelines for everyone. It is the job of a trainer to realize which clients are responders and which are nonresponders—and to manipulate program variables so that each client can be a responder (see Tables 1 and 2).

Heritage Family Study: Genetic Roots of Nonresponse

heritage study


AHA (American Heart Association). 2014. American Heart Association Recommendations for physical activity in adults. Accessed Jan. 11, 2016.
Artero, E.G., et al. 2012. Effects of muscular strength on cardiovascular risk factors and prognosis. Journal of Cardiopulmonary Rehabilitation & Prevention, 32 (6), 351-58.
Bacon, A.P., et al. 2013. VO2max trainability and high intensity interval training in humans: A meta-analysis. PLOS ONE, 8 (9), e73182.
Bouchard, C., & Rankinen, T. 2001. Individual differences in response to regular physical activity. Medicine & Science in Sports & Exercise, 33 (6, Suppl.), S446-51.
Bouchard, C., et al. 1999. Familial aggregation of VO2(max) response to exercise training: Results from the HERITAGE Family Study. Journal of Applied Physiology, 87 ( 3), 1003-08.
Bouchard, C., et al. 2012. Adverse metabolic response to regular exercise: Is it a rare or common occurrence? PLOS One, 7 (5), e37887.
Brudnak, M.A., Dundero, D., & Van Hecke, F.M. 2002. Are the ÔÇÿhard’ martial arts, such as the Korean martial art, taekwon-do, of benefit to senior citizens? Medical Hypotheses, 59 (4), 485-91.
Garber, C.E. et al. 2011. 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. Medicine & Science in Sports & Exercise, 43 (7), 1334-59.
McGuigan, M.R., et al. 2009. Eight weeks of resistance training can significantly alter body composition in children who are overweight or obese. Journal of Strength and Conditioning Research, 23 , 80-85.
NHGRI (National Human Genome Research Institute). 2015. DNA sequencing. Accessed Dec. 3, 2015.
Ross, R., de Lannoy, L., & Stotz, P.J. 2015. Separate effects of intensity and amount of exercise on interindividual cardiorespiratory fitness response. Mayo Clinic Proceedings, 90 (11), 1506-14.
Roth, S.M. 2007. Genetics Primer for Exercise Science and Health. Champaign, IL: Human Kinetics.
Seo, D.Y., et al. 2012. Yoga training improves metabolic parameters in obese boys. Korean Journal of Physiology & Pharmacology, 16 (3), 175-80.
Tremblay, A., Simoneau, J.-A., & Bouchard C. 1994. Impact of exercise intensity on body fatness and skeletal muscle metabolism. Metabolism, 43 (7), 814-18.
Westcott, W.L. 2012. Resistance training is medicine: Effects of strength training on health. Current Sports Medicine Reports, 11 (4), 209-16.

Mike Bracko, EdD

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