High Intensity Interval Training - "Can Less Be More?"

1. Sophie Brazell
Contact : BrazellS@cardiff.ac.uk
Biomedical Sciences (Physiology)
Can Less Be More ?

2. HIIT
HIIT = repeated bouts of high intensity activity completed at an
intensity that is greater than 90%VO2max .
Exercise bouts are separated by brief periods of low-intensity
work that allow a partial, but often not a full, recovery.
The purpose of HIT is to repeatedly stress the body to a greater
extent than that which is actually required during the activity.
Laursen et al 2002

3. Sprint
Rest
Repeat

4. Fastest land mammal Impressive endurance
HIIT trained ?
The Animal Kingdom

5. A typical HIIT session
3 minutes
HIIT
bout = 30 seconds sprint
1 minute recover
Repeat 4-6 times
3 min Cool Down
Total Workout Time:
~ 15 minutes
Time Spent working at
maximum capacity:
~ 3 minutes

6. How intense?
High Intensity Interval - 85% of Max HR
(220-Age) × 0.85
Active Recovery – 65%
of Max HR
(220-Age) × 0.65

7. Results After 2-6 Weeks!
Increased power
output
Improved
VO2max
Improved aerobic
and anaerobic
capacity
Improved
ability to deal
with lactic acid
Improved fat
metabolism
Improved
endurance
performance /work
capacity
Excess Post-Exercise
Oxygen
Consumption
Proven in Sedentary, Athletes and
Diseased Population

8. HIIT vs Endurance Training

9. Endurance Training Myth – Fat
Burning

10. Truthfully
The greater the intensity of your workout the more calories
you will burn
Intensity is the Key

11. After Burn Effect/EPOC
http://build-muscle-101.com/afterburn-effect/

12. The Evidence…….
Burgomaster et al. (2008) - HIIT protocol resulted in the same physiological
improvements as longer, low intensity running sesions despite a 90% reduction
in training volume and 67% reduction in training commitment
Naimo et al. (2014) – compared HIIT vs endurance training in ice hockey players
and found improvements in muscle thickness, peak power, mean power, sprint
speed and endurance test time with HIIT
Ma J.K. et al. (2013) - recorded increase VO2 peak of +19% and improved
anaerobic capacity by 12-14% after 6 weeks of HIIT training in active individuals
Gibala et al. (2012) HIIT associated with increased resting glycogen content,
decreased rate of glycogen utilisation and lactate production, enhanced
peripheral vascular structure and function, increased maximal oxygen uptake
and improved exercise performance, compared to endurance training

13. Jacobs et al. (2013) After 6 sessions of HIIT training increases aerobic respiration
and fat metabolism, increases in VO2peak, peak power output and time trial
performance.
Same responses seen in older less active populations (Hood M S et al. 2011) and
overweight/obese populations (Gillen J.B et al. 2013)
Gibala et al. (2006) recorded similar exercise induced adaption in HIIT ( 4-6 × 30s all
out cycling sprints at ~250% VO2peak interspersed by 4 minutes rest) and
endurance training (90-120min cycling at ~65% VO2peak) despite a time constraint
difference of ~ 8hrs
A recent meta-analysis of published HIIT experiments has concluded that the
efficiency of HIIT is comparable to endurance training with, on average, a 9.1%
increase in VO2max in HIIT groups compared to endurance training groups (Weston
K.S., 2014).

14. How HIIT Works
Exercise is a Stressor
The type of exercise has different stress
effects that result in different adaptions
Resistance = muscle building Endurance training

15. Endurance training relies on changes :
• Increasing Muscle acid levels
• Reactive Oxygen Species (ROS)
• Fluctuating Ca2+
• Glycogen levels
HIIT relies on changes :
• Increasing Muscle acid levels
• Reactive Oxygen Species (ROS)
• Fluctuating Ca2+
• Glycogen levels
What Causes the Adaptions?
Similar Mechanism
Similar Responses

16. Intervals and Intensity
By rapidly changing from recovery to fast
paced high intensities you are continuously
testing these mechanism
More stress in
HIIT than
endurance
training
More stress = Rapid adaptions
>

17. Mitochondria Power House
ATP
FAT
BURN

18. GIVE IT A GO!

19. 3 min warm up
1 min sprint
2 min recovery (rest or easy cycling)
1 min sprint
2 min recovery (rest or easy cycling)
1 min sprint
2 min recovery (rest or easy cycling)
Total time 12 min

20. Short exercise time, but rapid improvements
Work at hardest capacity for approx. 5 mins
Total workout time: approx. 15 mins
HIIT
FIT
Effective fat loss
Quicker metabolism
Improved aerobic capacity