High Intensity Interval Training (HIIT)

Transcription

1 High Intensity Interval Training (HIIT) Jim Cotter School of Physical Education, Sport & Exercise Sciences Chris Baldi Dunedin School of Medicine Teara.govt.nz

2 Outline Exercise; immensely under-acknowledged value What is exercise? (and PA more generally) Why incorporate HIIT into exercise regimes? How do you measure/achieve high intensity? What protocols/timing are recommended? Are there contraindications? versus adiposity in (lack of) health versus sedentary behaviour May need to be measured Is a pluripotent medicine Is more than a medicine

3 Exercise unmatched for pop n attributable benefit Pluripotent; against most noncommunicable diseases Category A evidence Nonlinear benefit-vs-dose Low risk Free Financially beneficial Self Society Booth & Laye J Physiol 2010 Saltin & Pedersen SJMSS 2006

4 Exercise (and other PA) is more than medicine For individuals and whanau

5 Exercise (and other PA) is more than medicine For society and communities Community engagement & connectedness crime / x CO 2 emissions / x Resource usage / x Traffic congestion Efficacy nzta.govt.nz Multi-fold savings of active transport and workplaces. To employer To community

6 Outline Exercise; immensely under-acknowledged value What is exercise? (and PA more generally) Why incorporate HIIT into exercise regimes? How do you measure/achieve high intensity? What protocols/timing are recommended? Are there contraindications? versus adiposity in (lack of) health versus sedentary behaviour May need to be measured Is a pluripotent medicine Is more than a medicine

7 Biophysically, what is exercise? wikipedia.org Multiple-sclerosis-research.blogspot.com x meritination.com dreamstime.com

8 Exercise improves (brain) function via several local and systemic mechanisms Lucas et al., J Cereb Blood Flow Metab (2015)

9 Better brain blood flow and its control (CO 2 reactivity (CVR CO2 )) in fitter people, both young and old These data X-sectional Fitter had CBF CBF control Young CBF Young CVR CO2 Old CBF Old CVR CO2 Bailey et al., Stroke (2013)

10 Outline Exercise; immensely under-acknowledged value What is exercise? (and PA more generally) Why incorporate HIIT into exercise regimes? How do you measure/achieve high intensity? What protocols/timing are recommended? Are there contraindications? versus adiposity in (lack of) health versus sedentary behaviour May need to be measured Is a pluripotent medicine Is more than a medicine

11 Meta analysis of high intensity intervals vs continuous Cardiorespiratory power Other effects Other observations of ours: Non responders to both Preferred not most potent Weston et al. Br J Sports Med (2014)

12 Impact on muscle is important Major glucose regulator/sink Many signalling and humoral factors released A major vascular bed Fiuza-Luces et al., Physiol 2013

13 High intensity esp. effective when low cardiac capacity Kemi & Wisløff. JCRP (2009)

14 HIIT is preferred?... Or just situational?

15 Many aspects still not clearly determined

16 Outline Exercise; immensely under-acknowledged value What is exercise? (and PA more generally) Why incorporate HIIT into exercise regimes? How do you measure/achieve high intensity? What protocols/timing are recommended? Are there contraindications? versus adiposity in (lack of) health versus sedentary behaviour May need to be measured Is a pluripotent medicine Is more than a medicine

17 What intensity if 3 4 minute intervals? Very, very hard Very hard Hard Somewhat hard Fairly light Very light Very, very light

18 Outline Exercise; immensely under-acknowledged value What is exercise? (and PA more generally) Why incorporate HIIT into exercise regimes? How do you measure/achieve high intensity? What protocols/timing are recommended? Are there contraindications? versus adiposity in (lack of) health versus sedentary behaviour May need to be measured Is a pluripotent medicine Is more than a medicine

19 What Profile of High-Intensity Exercise? 200% of work rate at VO 2 max Maximal aerobic power (%) Warm up HIT Traditionally recommended Time (min) Maximal aerobic power (%) Warm up/cool down Clinical HIT Traditionally recommended Time (min)

20 Outline Exercise; immensely under-acknowledged value What is exercise? (and PA more generally) Why incorporate HIIT into exercise regimes? How do you measure/achieve high intensity? What protocols/timing are recommended? Are there contraindications? versus adiposity in (lack of) health versus sedentary behaviour May need to be measured Is a pluripotent medicine Is more than a medicine

21 Recommendations for dosing How much? 150 min of moderate or 75 min of vigorous activity / wk Vigorous is valuable, esp. for metab, possibly for enjoyment ~2 resistance / wk Limit prolonged (>3 h?) sitting? Progression is critical When? Whenever they ll do it. Before breakfast and dinner?

22 Timing such exercise before meals may be beneficial Improved metabolic and cardiovascular control in pre diabetes Mean 24-h glucose 0.7 mmol/l. Also across the next day. Glucose stability by 35% Mean arterial pressure 7 mm Hg Francois et al. Diabetelogia 2014

23 What Factors profile? If considering just physiol. mediators of health outcomes: 200% of work rate at VO 2 max Warm up HIT Maximal aerobic power (%) Maximal aerobic power (%) Glucose control Muscle maint. BP control Aerobic capacity Arterial function Cerebrovascular ? ()?? Time (min) ?() Time (min)

24 Outline Exercise; immensely under-acknowledged value What is exercise? (and PA more generally) Why incorporate HIIT into exercise regimes? How do you measure/achieve high intensity? What protocols/timing are recommended? Are there contraindications? versus adiposity in (lack of) health versus sedentary behaviour May need to be measured Is a pluripotent medicine Is more than a medicine

25 Thank you Participants Monique Francois Kate Thomas Ashley Akerman Dr Luke Wilson Dr Sam Lucas Dr Chris Baldi Prof Phil Ainslie Mr Nigel Barrett