Transcript Slide 1
HDL cholesterol- is exercise the last line of Defence? Mr Iain Wain Exercise Physiologist, Calon Lan Cardiovascular Risk Cholesterol as the enemy? • Large proportion of MI’s in patients with normal overall CHC levels and low LDL “risk”. • But these still present with Low HDL-C and high Trygcleceride levels • 2% reduction in cardiovascular risk for every 1% increase in HDL-C. The science Bit • How does it all work? Drug Intervention trials • Nicotinic acids – Blocks breakdown of VLDL into LDL and converts to HDL – sig non-fatal MI and all cause mortality – Very difficult to tolerate (flushing effect) • Fibrates – lipoprotein lipase clearance – ? risk of side effects when used with statins – No significant in event rate Davisdon et al; Am J Cardiology, 2007 • CETP inhibitors – Block transfer of Lipoproteins from HDL to LDL HDL – Sig absolute HDL (61%) however, no in Atherosclerosis – Sig hypertension and cardiac events in patients with elevated Tryg levels US Food and Drug Administration, 2006 + Nissen et al; New England Journal of Med, 2007 Anyone tried exercise? Exercise Interventions • 1976- Wood et al – N=84 – 30% in HDL with trained athletes compared to “normal” control group. • 1977- Enger et al – N=220 – Sig in HDL in trained X-country skiers compared to sedentary control. – Greater difference in over 60 yr olds • 2001- HERITAGE study, Couillard et al – N= 675 – 3 x 60mins cycle ergometry over 20 weeks (45min @ 70% VO2max) – Sig overall in HDL of 4.9%, 18% in those with high triglyceride levels. Couillard, C. et al. Arterioscler Thromb Vasc Biol 2001;21:1226-1232 Copyright ©2001 American Heart Association Side effects? • You may actually get fitter and have a significantly improved quality of life • You might actually enjoy it? Cholesterol Ballooning effect • Stefanick et al; 1998 • N = 378 (males + post menopausal women) • 18 months, 3 Groups: • Diet only ( dietary fat content by 25%) • Exercise + Diet (µ of 16km brisk walking/week) • Sedentary control Diet Only DIET STOPS Sig LDL and therefore Total CHL LDL + HDL DIET Exercise + Diet Continued maintenance of TCHL EXERCISE + DIET LDL + /= HDL Lipoprotein A1 • Major component of HDL-C • Promotes promotion of cholesterol ethers • Responsible for “cleaning” of arterial walls • Cardio-protective properties even in patients with low HDL-C Zhu et al; 2005 J of Lipid Research • HERITAGE study attributed 3.7% in Apo 1 Couillard, C. et al. Arterioscler Thromb Vasc Biol 2001;21:1226-1232 Copyright ©2001 American Heart Association Couillard, C. et al. Arterioscler Thromb Vasc Biol 2001;21:1226-1232 Copyright ©2001 American Heart Association Proposed Study • 8 weeks interval training at 40% + 70% HRRmax vs 8 weeks traditional circuit style Phase 4 (40-60% HRRmax) • HDL-C - apoliproprotein 1a • HDL-C 1a / T-HDL ratio • T-CHL • Tryglycerides • Watch this space! THANK YOU FOR LISTENING [email protected]