The Science of High Intensity Interval Training-table

Study	Subjects	Study length	Protocol	Outcome	Best Result	Notes
Helgerud-2007	Moderately trained (V̇O2max 51-55)	3 days/week 8 weeks	Short HIIT 47x 15 seconds at 90-95% HRmax + 15 seconds at 70% HRmax	Raised V̇O2max 5.5%	Short and Long HIIT (no statistical difference)	All groups improved economy, with no differences, and Lactate Threshold unchanged as a percentage of V̇O2max
			Long HIIT 4x 4 min, 90-95% HRmax + 3 min at 70%max	Raised V̇O2max 7.2%
			Lactate Threshold run 24 min at 85% HRmax	V̇O2max unchanged
			Long Slow Distance 45 minutes at 70% HRmax	V̇O2max unchanged
TjonnaLee-2008	Untrained, metabolic syndrome patients	3 days/week 16 weeks	HIIT 4x 4 min at 90% HRmax + 3 min 70% HRmax total 40 min,	Raised V̇O2max 36%	HIIT	Same calories burned in each group Both groups had an equal reduction in body weight and blood pressure
			Continuous Moderate Exercise 47 min at 70% HRmax	Raised V̇O2max 16%
Gibala-2006	Recreationally active	2 weeks	HIIT 4-6x 30 seconds 'all out' + 4 min recovery Totals for two weeks, 135 minutes and 950 Kj	Same improvement in laboratory time trials	HIIT	Same improvement, but only 22% of the time commitment
			Continuous Moderate Exercise 90-120 min at 65% V̇O2peak Totals for two weeks, 630 minutes and 6500 Kj
Gorostiaga-1991	Sedentary	3 days/week 8 weeks	HIIT 30x 30 sec @ 100% V̇O2max + 30 sec rest	Raised V̇O2max 9-16% No change in blood Lactate during continuous exercise	HIIT	Same average work in each group
			Continuous Moderate Exercise 30 minutes at 50% V̇O2max	Raised V̇O2max 5-7% Reduced blood Lactate during continuous exercise by nearly 50%
Franch-1998	36 recreational runners	3 days/week at high intensity Plus 3 runs/week <= 65% HRmax 6 weeks	Short HIIT 30-40x 15 sec run, 15 sec rest Avg ~3.0 Km/workout 92% HRmax	Time to exhaustion increased 65% Running Economy improved 0.9%	Continuous High Intensity	Better improvements from continuous training than HIIT, but the continuous training is at an unusually high intensity that is probably close to a 10K race, three times a week.
			Long HIIT 4-6x 4 min run, 2 min rest Avg ~5.6 Km/workout 94% HRmax	Time to exhaustion increased 67% Running Economy improved 3.0%
			Continuous High Intensity 20-30 minutes Avg ~6.4 Km/workout 93% HRmax	Time to exhaustion increased 94% Running Economy improved 3.1%
BurgomasterHowarth-2007	20 Untrained	HIIT 3x week Continuous 5x week 6 weeks	HIIT 4-6x 30 seconds 'all out', 4.5 min rest 1.5 hours/week ~225 Kj/week	Both increased V̇O2peak by ~5%	HIIT	Similar changes in HIIT for 10% of the workload and 30% of the time of continuous training.
			Continuous Moderate Exercise 40-60 min at 65% V̇O2peak 4.5 hours/week 2250 Kj/week
Trapp-2008	34 sedentary women	45 workouts over 15 weeks	HIIT 60x 8 seconds 'all out', 12 seconds rest (5 min Warmup, 20 min conditioning, 5 min Cooldown)	Increased V̇O2peak 24% 5 pound/2.5 Kg reduction in body fat Significant 31% reduction in fasting insulin Significant reduction in Leptin	HIIT	HIIT produced similar improvements in fitness for a lower time commitment, as well as a reduction in body fat that was not seen with continuous exercise.
			Continuous Moderate Exercise 40 minutes at 60% V̇O2peak	Increased V̇O2peak 19% 1 pound/0.5 Kg gain in body fat Non-significant 9% reduction in fasting insulin No change in Leptin
Tabata-1996	14 varsity level collage athletes (V̇O2max ~50)	5 days/week 6 weeks	HIIT 4 days/week 7-8x (30 seconds at 170% V̇O2max + 10 seconds rest) 1 day/week 30 min at 70% V̇O2max + 4x (30 seconds at 170% V̇O2max + 10 seconds rest)	Raised V̇O2max by 14.5% Increased anaerobic capacity by 28%	HIIT	HIIT produced a greater improvement in V̇O2max for far less time commitment
			Continuous Moderate Exercise 60 minutes at 70% V̇O2max	Raised V̇O2max by 9.5% No change in anaerobic capacity
EarnestTjønna-2013	26 healthy overweight men (BMI 25-30)	3 days/week 10 weeks	4x HIIT 10 min Warmup 4x 4 min at 90% HRmax + 3 min 70% HRmax 5 min Cooldown total 40 min	Raised V̇O2max by 13% Work economy improved by 13% Systolic blood pressure decreased 3.2 mmHg Diastolic blood pressure decreased 6.3 mmHg	Similar results with both protocols	This study showed remarkable results using a single high intensity bout of exercise.
			1x HIIT 10 min Warmup 4 min at 90% HRmax 5 min Cooldown total 19 min	Raised V̇O2max by 10% Work economy improved by 14% Systolic blood pressure decreased 6.2 mmHg Diastolic blood pressure decreased 7.7 mmHg