Lose Weight in 8 Seconds?

Researchers at the University of Sydney and the Garvan institute(1) studied 45 20 year old women who had been designated as overweight over 15 weeks. The women were assigned to a high intensity intermittent exercise (HIIE) workout at random and to a steady state exercise (SSE) (control group).

The high intensity workout consisted of an 8-second stationary bicycle sprint (rpm range of around 100-120) followed immediately by 12 seconds pedaling as slow as possible. This cycle was then continuously repeated for a 20 minute workout (ie the women completed 60 sprints within the workout). The participants started the HIIE exercise for around 5 minutes for the first week and then built up the time and intensity of sprint over the remaining weeks.

---

---

The SSE involved three 40-minute continuous stationary bicycle exercises per week (at a target of 60% of peak oxygen uptake). Both workouts utilised a 5-minute warm-up and cool-down.

The results of the study were extremely favourable for the high intensity intermittent exercise group.

• HIIE group lost an average of 2.5kg of body fat after the 15 weeks. The SSE group actually had a slight increase in body fat slightly by .5 kg
• The women who lost the least fat in the HIIE group were had the lowest starting BMIs (below 20kg/m2) so when these were removed from the data average fat lost for the rest of the women was 3.9 kg.
• The fat loss in the HIIE surprising disproportionate with the women losing more fat off their legs than their arms. They also had significant fat loss from their abdomens.
• Both exercise groups raised their aerobic fitness; the high intensity group by 26% whereas the steady state group by only 19%.
• HIIE women decreased fasting insulin by 31% and SSE women by 8%, which may have useful benefits for diabetes sufferers.

The researchers concluded that the success of the high intensity interval workout may be due to higher amounts of compounds called catecholamines that are produced in increasing amounts when interval sprinting and the chemical reaction that follows produces greater fat burning. The scientists believe the regime would also be applicable to swimming, walking, running and rowing (although longer intervals than 8 seconds may not be appropriate for overweight individuals).

(1)Metabolic response of trained and untrained women during high-intensity intermittent cycle exercise E. Gail Trapp, Donald J. Chisholm, and Stephen H. Boutcher
Am J Physiol Regul Integr Comp Physiol 293: R2370-R2375, 2007

---

---

Other General Health Articles