Lack of time is frequently
cited as one of the main barriers to people becoming or staying
physically active. High-intensity workouts have begun to tackle this
problem, allowing people to get maximum health benefits while working
out for a shorter time.
Time-poor people who do fewer repetitions during high-intensity
interval training (HIIT) workouts may get better fitness benefits than
those who complete more, suggested a University of Stirling analysis.
‘Improved cardiorespiratory fitness does not suffer when people complete fewer sprint repetitions and that this may even produce better results.’
Experts from Scotland's University for Sporting Excellence have
reviewed existing studies that investigate the benefits of regularly
performing repetitions of a special type of high-intensity cycle sprint
known as 'supramaximal'. They found doing fewer repetitions of these
sprint intervals on a bike may lead to greater improvements in
Dr. Niels Vollaard, Lecturer in Health and Exercise Science in the
Faculty of Health Sciences and Sport, said: "We found improved cardiorespiratory fitness does not suffer when
people complete fewer sprint repetitions and that this may even produce
better results. The optimal number of repetitions appears to be just
two, so workouts based on supramaximal sprints can be kept very short
without compromising on the results."
The findings of this research are only applicable to 'supramaximal'
exercise, which requires specialized exercise bikes that enable very
high exercise intensities. Whether HIIT workouts at lower intensities
also benefit from a low number of sprint repetitions is not yet known.
Previously, it has been assumed that performing more repetitions of
high-intensity exercise will produce greater improvements in
In this analysis, published in the leading journal Medicine and Science in Sports and Exercise
scientists found that after performing two maximal sprints, each
additional sprint in a training session reduced the overall improvement
in fitness by around 5% on average.
Dr. Vollaard added: "For the first time, we have evidence to suggest
an indicator of fitness levels is improved more by doing fewer
repetitions of high-intensity exercise. We are currently performing
studies to investigate the physiological mechanisms that may explain
this unexpected finding."
"To encourage more people to become active and help increase the
health of the population, we need to investigate the optimal duration
and number of sprint intervals people could undertake on a bike, while
getting the same benefits as longer sessions."
Fitness levels were measured by VO2max, the maximal amount of oxygen
the body is capable of utilizing in one minute, which is accepted as
one of the best indicators of future health and risk of premature death.
However, studying other indicators of health and fitness, including
blood pressure and insulin sensitivity, will give a fuller picture of
how the body responds to different types of HIIT workouts.