The Effects of a 4-Minute Interval Training Protocol on Cardiorespiratory and Metabolic Risk Factors

Transcription

1 The Effects of a 4-Minute Interval Training Protocol on Cardiorespiratory and Metabolic Risk Factors Arnt Erik Tjønna 1, Ingeborg Megaard Leinan 2, Anette Thoresen Bartnes 2, Bjørn M Jenssen 2, Richard A. Winett 3, Ulrik Wisløff 1,4 1.Norwegian University of Science and Technology, 2.Norwegian University of Science and Technology, 3. Virginia Tech, USA; 4. Norwegian University of Science and Technology

2 PA vs CRF PA and Public Health Policy Prospective Studies ACLS, HUNT clearly point to CRF CRF inapprorpriately translated to PA

3 Re-Analysis of ACLS* N=~42,000 Reference Group Not meet PA, Unfit (<20%) Meet PA, not CRF minimal risk reduction Meet PA and CRF - ~40% risk reduction Meet CRF, not PA - ~40% risk reduction Historically other analyses of ACLS CRF trumps other risk factors *Lee et al. Brit J Sports Med D-C Lee, X Sui, F B Ortega Y-S Kim, T S Church, R A Winett, U Ekelund, P T Katzmarzyk, S N Blair

4 HUNT 1/ Week Vigorous reduces risk minutes CRF Trumps other risk factors

5 Historically Ken Cooper Dawn of the Aerobics Revolution Air Force Studies CRF can be increased in very brief protocols (5 minutes; Aerobics. 1968; p.23) Never Followed Up Lost the Thread Denigrated Skeletal Muscle Mass and Importance to Health Led to primarily Long Slow Distance LSD

6 Efficient, Effective Way to Increase Interval Training Different Protocols CRF Wisloff Group Norway+ Gibala Group Canada+ Tabata Group Japan +Note: Also experimenting with one several minutes hard segment

7 Interval Training Who will perform interval training? Will it be aversive? Will people expire in the process? Does it really produce better results than typical moderate intensity training?

8 Wisloff Group 4 x 4 protocol Warm-up; 4 minutes 90% HRmax (~80% aerobic capacity), 4 minutes easy x 4 Applications MetS, Cardiac patients, hypertension Energy Equivalent Moderate (70% HRmax) AT 3/Week

9 Outcomes 4 X 4 > Moderate on virtually all measures and dramatically so for CRF and blood pressure No adverse events 4 x 4 challenging, motivating Moderate AT boring Effects are INTENSITY Dependent Interval Training should be prescription! Kemi & Wisloff. J Cardio Pulmonary Rehabil Prev. 2010

10 Interval Training Can Be Enjoyable!

11 Threshold Model Winett & Carpinelli What s the stimulus? Most of Effect of AT pass an intensity threshold for a few minutes Graded Exercise Protocol ( GXP ) 3-4 minute warm-up to 70% aerobic capacity; 3-4 minutes workpart at 75% to 80%, 3-4 minutes graded cooldown 2/week Prescriptive and Progressive Increase ~1.5 METs Winett et al, J Behav Med. 2003; Lutes et al., Annals Behav Med

12 Study 4 x 4 vs 1 x 4 3/week Supervised 10 Weeks 26 previously untrained, slightly overweight men, age, Random Assignment

13 Outcomes The 4-AIT and 1-AIT increased VO2max by 13% (~6.5 ml kg-1 min- 1) and 10% (~5.0 ml kg-1 min-1) (p<0.01), respectively (no group difference).

14 Outcomes Stroke volume indicated by peak oxygen pulse (VO2max/maximal heart rate) increased by 15% in 4-AIT (p<0.01) and 14% (p<0.01) in 1-AIT (no group difference).

15 Outcomes Both 4-AIT and 1-AIT decreased mean arterial blood pressures, by ~6 mmhg (both, p<0.05)

16 Outcomes Both groups reduced body fat by about 2.5%.

17 Outcomes 4-AIT and 1-AIT induced significant reductions in fasting glucose by 5% and 6%, respectively (p<0.05)

18 Translation Issues Public Health Needs to Focus much more on CRF (and Strength) 1 x 4 or GXP 4 minutes, walk quickly up hill or 6-10 flights of stairs 2-3/week RPE of 16/20 on Borg Scale

19 Translation Issues Middle age to Older Adults Long duration AT and PA is catabolic Does little to preserve CRF, strength, lean body mass Move away from the endurance focused phenotype with minimal strength and lean body mass

20 Translation Issues Focus on Different Phenotype Resistance Training, GXP or 1 x 4, some PA, not just sit all day DASH (or other) nutrition pattern with quality protein throughout the day and protein timing Reduce bodyfat and weight, preserve lean body mass while increasing/maintaining CRF, strength Phillips & Winett. Curr Rev Sports Med. 2010; Davy & Winett, Multiple PI s, NIDDK, Maintaining Resistance Training