5 Discussion 46
5.4 Summary and Conclusion 54
Currently, western society has reached a level of physical inactivity that far outweighs prior generations (Booth, Chakravarthy, & Spangenburg, 2002). Further, it is clear that physical inactivity is a risk factor for various cardiovascular diseases such as atherosclerosis. Likely, disease of conduit arteries as assessed via endothelial
dysfunction is an early manifestation of atherosclerosis (Vita, 2005). Several studies have revealed that endurance exercise training is an intervention that can improve endothelial vascular function in a diseased or at risk population (Green et al., 2004; Maiorana et al., 2003; Moyna & Thompson, 2004; Walsh et al., 2003). However, studies on exercise training and endothelial vascular function in healthy populations are far less common and the results are inconsistent (Green et al., 2011). Further, there is a large void of research on the effects of exercise training on the endothelial vascular function of young healthy women. Interestingly, moderate intensity endurance exercise is used commonly as the training stimulus to improve endothelial function in both healthy and diseased populations, despite research that denotes many similar and/or greater training adaptations with SIT (Burgomaster, Heigenhauser, & Gibala, 2006; Green et al., 2011; Macpherson et al.,2011; Maiorana et al., 2001; Thijssen et al., 2011; Tinken et al., 2010). However, high intensity exercise training induces greater oxidative stress, which could be
positive (via its increased antioxidant defense) or negative (via blunted endothelial function) (Atalay et al., 1996; Bloomer, 2007; Elosua et al., 2003; Gomez-Cabrera, Vina, & Ji, 2009; Laughlin & Roseguini, 2008; Sen, Atalay, & Hanninen, 1994).
The current study examined the effects of SIT on endothelial vascular function (via FMD) in 41 young recreationally active men and women. It was hypothesized that the longer exercise bout (up to 7 x 45 s) SIT protocol would improve SFA endothelial function and hemodynamic properties. In the women, SIT decreased time to peak dilation and increased flow mediated dilation. Surprisingly, SIT had no effect on any endothelial function or hemodynamic measures in the men.
These results suggest that SIT improved endothelial vascular function in young recreationally active women. This improvement could be due to changes in the NO response. The observed gender difference may be due to differences in the men’s baseline vascular function attributed to exercise training status, greater oxidative stress, and/or vascular structural remodeling that prevented endothelial vascular functional improvements in the male participants. Future studies on the effects of SIT on endothelial vascular function in young healthy individuals are needed to establish the blood flow pattern (retrograde and antegrade) associated with SIT, in order to quantify any associated shear stress stimulus as well as to document whether increases in endothelial phenotype sensitivity contribute to different vascular adaptations.
Longitudinal training studies that include measures of vascular structural remodeling would be welcomed to assess possible gender differences in structural and vascular adaptations with time.
In conclusion, six weeks of SIT improved endothelial function (perhaps mediated
by increased NO response) in young women. However, six weeks of SIT did not improve endothelial function in young men.
References
Atalay, M., Seene, T., Hanninen, O., & Sen, C. K. (1996). Skeletal muscle and heart
antioxidant defences in response to sprint training. Acta Physiologica Scandinavica,
158(2), 129-134.
Bae, J. H., Bassenge, E., Lee, H. J., Park, K. R., Park, C. G., Park, K. Y., et al. (2001). Impact of postprandial hypertriglyceridemia on vascular responses in patients with
coronary artery disease: Effects of ACE inhibitors and fibrates. Atherosclerosis, 158(1),
165-171.
Beckman, J. A., Goldfine, A. B., Gordon, M. B., Garrett, L. A., Keaney, J. F.,Jr, & Creager, M. A. (2003). Oral antioxidant therapy improves endothelial function in type 1
but not type 2 diabetes mellitus. American Journal of Physiology.Heart and Circulatory
Physiology, 285(6), H2392-8. doi:10.1152/ajpheart.00403.2003
Berdeaux, A., Ghaleh, B., Dubois-Rande, J. L., Vigue, B., Drieu La Rochelle, C., Hittinger, L., et al. (1994). Role of vascular endothelium in exercise-induced dilation of
large epicardial coronary arteries in conscious dogs. Circulation, 89(6), 2799-2808.
Bergfeld, G. R., & Forrester, T. (1992). Release of ATP from human erythrocytes in
response to a brief period of hypoxia and hypercapnia. Cardiovascular Research, 26(1),
40-47.
Bergholm,R.,Makimattila, S., Valkonen, M., Liu, M.L., Lahdenpera, S., Taskinen, M.R., et al. (1999). Intense physical training decreases circulation antioxidants and
endothelium-dependent vasodilation in vivo. Atherosclerosis, 145(2), 341-349.
Black, M. A., Cable, N. T., Thijssen, D. H., & Green, D. J. (2008). Importance of
measuring the time course of flow-mediated dilatation in humans. Hypertension, 51(2),
Bloomer, R. J. (2007). The role of nutritional supplements in the prevention and
treatment of resistance exercise-induced skeletal muscle injury. Sports Medicine, 37(6),
519-532.
Booth, F. W., Chakravarthy, M. V., & Spangenburg, E. E. (2002). Exercise and gene
expression: Physiological regulation of the human genome through physical activity. The
Journal of Physiology, 543(Pt 2), 399-411.
Boron, W. F., & Boulpaep, E. L. (2003). Medical physiology :A cellular and molecular
approach (1st ed.). Philadelphia, PA: W.B. Saunders.
Burgomaster, K. A., Heigenhauser, G. J., & Gibala, M. J. (2006). Effect of short-term sprint interval training on human skeletal muscle carbohydrate metabolism during
exercise and time-trial performance. Journal of Applied Physiology (Bethesda, Md.:
1985), 100(6), 2041-2047. doi:10.1152/japplphysiol.01220.2005
Burgomaster, K. A., Hughes, S. C., Heigenhauser, G. J., Bradwell, S. N., & Gibala, M. J. (2005). Six sessions of sprint interval training increases muscle oxidative potential and
cycle endurance capacity in humans. Journal of Applied Physiology (Bethesda, Md.:
1985), 98(6), 1985-1990. doi:10.1152/japplphysiol.01095.2004
Burgomaster, K. A., Howarth, K. R., Phillips, S. M., Rakobowchuk, M., MacDonald, M. J., & Gibala, M. J. (2007). Sprint versus endurance training: Metabolic adaptations in
working human skeletal muscle. Faseb Journal, 21(5), A575-A575.
Calbet, J. A., Jensen-Urstad, M., van Hall, G., Holmberg, H. C., Rosdahl, H., & Saltin, B. (2004). Maximal muscular vascular conductances during whole body upright exercise in
humans. The Journal of Physiology, 558(Pt 1), 319-331.
doi:10.1113/jphysiol.2003.059287
Celermajer, D. S., Sorensen, K. E., Gooch, V. M., Spiegelhalter, D. J., Miller, O. I., Sullivan, I. D., et al. (1992). Non-invasive detection of endothelial dysfunction in
Clarkson, P., Montgomery, H. E., Mullen, M. J., Donald, A. E., Powe, A. J., Bull, T., et
al. (1999). Exercise training enhances endothelial function in young men. Journal of the
American College of Cardiology, 33(5), 1379-1385.
Clifford, P. S. (2011). Local control of blood flow. Advances in Physiology Education,
35(1), 5-15. doi:10.1152/advan.00074.2010
Clifford, P. S., & Hellsten, Y. (2004). Vasodilatory mechanisms in contracting skeletal
muscle. Journal of Applied Physiology (Bethesda, Md.: 1985), 97(1), 393-403.
doi:10.1152/japplphysiol.00179.2004
Cooke, J. P., & Dzau, V. J. (1997). Nitric oxide synthase: Role in the genesis of vascular
disease. Annual Review of Medicine, 48, 489-509. doi:10.1146/annurev.med.48.1.489
Corretti, M. C., Anderson, T. J., Benjamin, E. J., Celermajer, D., Charbonneau, F., Creager, M. A., et al. (2002). Guidelines for the ultrasound assessment of endothelial- dependent flow-mediated vasodilation of the brachial artery: A report of the international
brachial artery reactivity task force. Journal of the American College of Cardiology,
39(2), 257-265.
Creager, M. A., Cooke, J. P., Mendelsohn, M. E., Gallagher, S. J., Coleman, S. M., Loscalzo, J., et al. (1990). Impaired vasodilation of forearm resistance vessels in
hypercholesterolemic humans. The Journal of Clinical Investigation, 86(1), 228-234.
doi:10.1172/JCI114688
Debasso, R., Astrand, H., Bjarnegard, N., Ryden Ahlgren, A., Sandgren, T., & Lanne, T. (2004). The popliteal artery, an unusual muscular artery with wall properties similar to
the aorta: Implications for susceptibility to aneurysm formation? Journal of Vascular
Surgery : Official Publication, the Society for Vascular Surgery [and] International
Society for Cardiovascular Surgery, North American Chapter, 39(4), 836-842.
Doshi, S. N., Naka, K. K., Payne, N., Jones, C. J., Ashton, M., Lewis, M. J., et al. (2001). Flow-mediated dilatation following wrist and upper arm occlusion in humans: The
contribution of nitric oxide. Clinical Science (London, England : 1979), 101(6), 629-635.
Ellis, C. G., Milkovich, S., & Goldman, D. (2012). What is the efficiency of ATP signaling from erythrocytes to regulate distribution of O (2) supply within the
microvasculature? Microcirculation (New York, N.Y.: 1994), 19(5) , 440-450.
Elosua, R., Molina, L., Fito, M., Arquer, A., Sanchez-Quesada, J. L., Covas, M. I., et al. (2003). Response of oxidative stress biomarkers to a 16-week aerobic physical activity program, and to acute physical activity, in healthy young men and women.
Atherosclerosis, 167(2), 327-334.
Endemann, D. H., & Schiffrin, E. L. (2004). Endothelial dysfunction. Journal of the
American Society of Nephrology : JASN, 15(8), 1983-1992.
doi:10.1097/01.ASN.0000132474.50966.DA
Engler, M. M., Engler, M. B., Malloy, M. J., Chiu, E. Y., Schloetter, M. C., Paul, S. M., et al. (2003). Antioxidant vitamins C and E improve endothelial function in children with hyperlipidemia: Endothelial assessment of risk from lipids in youth (EARLY) trial.
Circulation, 108(9), 1059-1063. doi:10.1161/01.CIR.0000086345.09861.A0
Fronek, A. (1989). Noninvasive diagnostics in vascular disease. New York: McGraw-
Hill Book, Co.
Furchgott, R. F., & Zawadzki, J. V. (1980). The obligatory role of endothelial cells in the
relaxation of arterial smooth muscle by acetylcholine. Nature, 288(5789), 373-376.
Garber, C. E., Blissmer, B., Deschenes, M. R., Franklin, B. A., Lamonte, M. J., Lee, I. M., et al. (2011). American college of sports medicine position stand. quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: Guidance for prescribing exercise.
Medicine and Science in Sports and Exercise, 43(7), 1334-1359.
Gibala, M. J., Little, J. P., van Essen, M., Wilkin, G. P., Burgomaster, K. A., Safdar, A., et al. (2006). Short-term sprint interval versus traditional endurance training: Similar
initial adaptations in human skeletal muscle and exercise performance. The Journal of
Physiology, 575(Pt 3), 901-911. doi:10.1113/jphysiol.2006.112094
Ghiadoni, L., Faita, F., Salvetti, M., Cordiano, C., Biggi, A., Puato, M.,et al. (2012). Assessment of flow-mediated dilation reproducibility: A nationwide multicenter study.
Journal of Hypertension, 30(7), 13991405. doi:10.1097/HJH.0b013e328353f222
Gomez-Cabrera, M. C., Vina, J., & Ji, L. L. (2009). Interplay of oxidants and
antioxidants during exercise: Implications for muscle health. The Physician and
Sportsmedicine, 37(4), 116-123. doi:10.3810/psm.2009.12.1749
Goto, C., Higashi, Y., Kimura, M., Noma, K., Hara, K., Nakagawa, K., et al. (2003). Effect of different intensities of exercise on endothelium-dependent vasodilation in
humans: Role of endothelium-dependent nitric oxide and oxidative stress. Circulation,
108(5), 530-535.
Green, D. (2005). Point: Flow-mediated dilation does reflect nitric oxide-mediated
endothelial function. Journal of Applied Physiology (Bethesda, Md.: 1985), 99(3), 1233-
4; discussion 1237-8. doi:10.1152/japplphysiol.00601.2005
Green, D. J., Bilsborough, W., Naylor, L. H., Reed, C., Wright, J., O'Driscoll, G., et al. (2005). Comparison of forearm blood flow responses to incremental handgrip and cycle
ergometer exercise: Relative contribution of nitric oxide. The Journal of Physiology,
562(Pt 2), 617-628. doi:10.1113/jphysiol.2004.075929
Green, D. J., Fowler, D. T., O'Driscoll, J. G., Blanksby, B. A., & Taylor, R. R. (1996).
Endothelium-derived nitric oxide activity in forearm vessels of tennis players. Journal of
Applied Physiology (Bethesda, Md.: 1985), 81(2), 943-948.
Green, D. J., Maiorana, A., O'Driscoll, G., & Taylor, R. (2004). Effect of exercise
training on endothelium-derived nitric oxide function in humans. The Journal of
Green, D. J., Spence, A., Halliwill, J. R., Cable, N. T., & Thijssen, D. H. (2011). Exercise
and vascular adaptation in asymptomatic humans. Experimental Physiology, 96(2), 57-
70. doi:10.1113/expphysiol.2009.048694
Green, D. J., Spence, A., Rowley, N., Thijssen, D. H., & Naylor, L. H. (2012). Vascular
adaptation in athletes: Is there an 'athlete's artery'? Experimental Physiology, 97(3), 295-
304. doi:10.1113/expphysiol.2011.058826
Green, D. J., Walsh, J. H., Maiorana, A., Best, M. J., Taylor, R. R., & O'Driscoll, J. G. (2003). Exercise-induced improvement in endothelial dysfunction is not mediated by
changes in CV risk factors: Pooled analysis of diverse patient populations. American
Journal of Physiology.Heart and Circulatory Physiology, 285(6), H2679-87.
doi:10.1152/ajpheart.00519.2003
Green, D. J., Walsh, J. H., Maiorana, A., Burke, V., Taylor, R. R., & O'Driscoll, J. G. (2004). Comparison of resistance and conduit vessel nitric oxide-mediated vascular
function in vivo: Effects of exercise training. Journal of Applied Physiology (Bethesda,
Md.: 1985), 97(2), 749-55; discussion 748. doi:10.1152/japplphysiol.00109.2004
Greenwald, S. E. (2007). Ageing of the conduit arteries. The Journal of Pathology,
211(2), 157-172. doi:10.1002/path.2101
Hambrecht, R., Adams, V., Erbs, S., Linke, A., Krankel, N., Shu, Y., et al. (2003). Regular physical activity improves endothelial function in patients with coronary artery
disease by increasing phosphorylation of endothelial nitric oxide synthase. Circulation,
107(25), 3152-3158. doi:10.1161/01.CIR.0000074229.93804.5C
Harris, R. A., Nishiyama, S. K., Wray, D. W., & Richardson, R. S. (2010). Ultrasound
assessment of flow-mediated dilation. Hypertension, 55(5), 1075-1085.
doi:10.1161/HYPERTENSIONAHA.110.150821
Hashimoto, M., Akishita, M., Eto, M., Ishikawa, M., Kozaki, K., Toba, K., et al. (1995). Modulation of endothelium-dependent flow-mediated dilatation of the brachial artery by
Hayashi, T., Yamada, K., Esaki, T., Kuzuya, M., Satake, S., Ishikawa, T., et al. (1995).
Estrogen increases endothelial nitric oxide by a receptor-mediated system. Biochemical
and Biophysical Research Communications, 214(3), 847-855.
doi:10.1006/bbrc.1995.2364
Haskell, W. L., Lee, I. M., Pate, R. R., Powell, K. E., Blair, S. N., Franklin, B. A., et al. (2007). Physical activity and public health: Updated recommendation for adults from the
american college of sports medicine and the american heart association. Circulation,
116(9), 1081 - 1093.
Hazell, T. J., MacPherson, R. E. K., Gravelle, B. M. R., & Lemon, P. W. R. (2010). 10 or 30-S sprint interval training bouts enhance both aerobic and anaerobic performance.
European Journal of Applied Physiology, 110(1), 153-160. doi:10.1007/s00421-010-
1474-y
Hopkins, N. D., Stratton, G., Tinken, T. M., McWhannell, N., Ridgers, N. D., Graves, L. E., et al. (2009). Relationships between measures of fitness, physical activity, body
composition and vascular function in children. Atherosclerosis, 204(1), 244-249.
doi:10.1016/j.atherosclerosis.2008.09.004
Jarvisalo, M. J., Jartti, L., Marniemi, J., Ronnemaa, T., Viikari, J. S., Lehtimaki, T., et al. (2006). Determinants of short-term variation in arterial flow-mediated dilatation in
healthy young men. Clinical Science (London, England : 1979), 110(4), 475-482.
doi:10.1042/CS20050333
Jones, S. P., & Bolli, R. (2006). The ubiquitous role of nitric oxide in cardioprotection.
Journal of Molecular and Cellular Cardiology, 40(1), 16-23.
doi:10.1016/j.yjmcc.2005.09.011
Kawano, H., Fujimoto, K., Higuchi, M., & Miyachi, M. (2009). Effect of combined
resistance and aerobic training on reactive hyperemia in men. The Journal of
Kawano, H., Motoyama, T., Kugiyama, K., Hirashima, O., Ohgushi, M., Fujii, H., et al. (1997). Gender difference in improvement of endothelium-dependent vasodilation after
estrogen supplementation. Journal of the American College of Cardiology, 30(4), 914-
919.
Kooijman, M., Thijssen, D. H., de Groot, P. C., Bleeker, M. W., van Kuppevelt, H. J., Green, D. J., et al. (2008). Flow-mediated dilatation in the superficial femoral artery is
nitric oxide mediated in humans. The Journal of Physiology, 586(4), 1137-1145.
doi:10.1113/jphysiol.2007.145722
Kremkau, F. W. (1990). Doppler ultrasound :Principles and instruments. Philadelphia:
Saunders.
Langille, B. L., & O'Donnell, F. (1986). Reductions in arterial diameter produced by
chronic decreases in blood flow are endothelium-dependent. Science (New York, N.Y.),
231(4736), 405-407.
Laughlin, M. H. (1987). Skeletal muscle blood flow capacity: Role of muscle pump in
exercise hyperemia. The American Journal of Physiology, 253(5 Pt 2), H993-1004.
Laughlin, M. H., McAllister, R. M., Jasperse, J. L., Crader, S. E., Williams, D. A., & Huxley, V. H. (1996). Endothelium-medicated control of the coronary circulation.
exercise training-induced vascular adaptations. Sports Medicine (Auckland, N.Z.), 22(4),
228-250.
Laughlin, M. H., Newcomer, S. C., & Bender, S. B. (2008). Importance of hemodynamic
forces as signals for exercise-induced changes in endothelial cell phenotype. Journal of
Applied Physiology (Bethesda, Md.: 1985), 104(3), 588-600.
doi:10.1152/japplphysiol.01096.2007
Laughlin, M. H., & Roseguini, B. (2008). Mechanisms for exercise training-induced increases in skeletal muscle blood flow capacity: Differences with interval sprint training
versus aerobic endurance training. Journal of Physiology and Pharmacology : An Official
Laughlin, M. H., Rubin, L. J., Rush, J. W., Price, E. M., Schrage, W. G., & Woodman, C. R. (2003). Short-term training enhances endothelium-dependent dilation of coronary
arteries, not arterioles. Journal of Applied Physiology (Bethesda, Md.: 1985), 94(1), 234-
244. doi:10.1152/japplphysiol.00246.2002
Laughlin, M. H., Turk, J. R., Schrage, W. G., Woodman, C. R., & Price, E. M. (2003).
Influence of coronary artery diameter on eNOS protein content. American Journal of
Physiology.Heart and Circulatory Physiology, 284(4), H1307-12.
doi:10.1152/ajpheart.00792.2002
Liuni, A., Luca, M. C., Lisi, M., Dragoni, S., di Stolfo, G., Mariani, J. A., et al. (2010). Observations of time-based measures of flow-mediated dilation of forearm conduit
arteries: Implications for the accurate assessment of endothelial function. American
Journal of Physiology.Heart and Circulatory Physiology, 299(3), H939-45.
doi:10.1152/ajpheart.00271.2010
Lloyd-Jones, D. M., Hong, Y., Labarthe, D., Mozaffarian, D., Appel, L. J., Van Horn, L., et al. (2010). Defining and setting national goals for cardiovascular health promotion and disease reduction the American Heart Association's strategic impact goal through 2020
and beyond RID C-5899-2009. Circulation, 121(4), 586-613.
doi:10.1161/CIRCULATIONAHA.109.192703
Macpherson, R. E., Hazell, T. J., Olver, T. D., Paterson, D. H., & Lemon, P. W. (2011). Run sprint interval training improves aerobic performance but not max cardiac output.
Medicine and Science in Sports and Exercise, 43(1),115-122
Maiorana, A., O'Driscoll, G., Cheetham, C., Dembo, L., Stanton, K., Goodman, C., et al. (2001). The effect of combined aerobic and resistance exercise training on vascular
function in type 2 diabetes. Journal of the American College of Cardiology, 38(3), 860-
866.
Maiorana, A., O'Driscoll, G., Dembo, L., Goodman, C., Taylor, R., & Green, D. (2001). Exercise training, vascular function, and functional capacity in middle-aged subjects.
Maiorana, A., O'Driscoll, G., Taylor, R., & Green, D. (2003). Exercise and the nitric
oxide vasodilator system. Sports Medicine (Auckland, N.Z.), 33(14), 1013-1035.
McDermott, M. M., Liu, K., Carroll, T. J., Tian, L., Ferrucci, L., Li, D., et al. (2011). Superficial femoral artery plaque and functional performance in peripheral arterial
disease: Walking and leg circulation study (WALCS III). JACC.Cardiovascular Imaging,
4(7), 730-739. doi:10.1016/j.jcmg.2011.04.009
Messina, E. J., Weiner, R., & Kaley, G. (1977). Arteriolar reactive hyperemia:
Modification by inhibitors of prostaglandin synthesis. The American Journal of
Physiology, 232(6), H571-5.
Monnink, S. H., van Haelst, P. L., van Boven, A. J., Stroes, E. S., Tio, R. A., Plokker, T. W., et al. (2002). Endothelial dysfunction in patients with coronary artery disease: A
comparison of three frequently reported tests. Journal of Investigative Medicine : The
Official Publication of the American Federation for Clinical Research, 50(1), 19-24.
Moore, L. C., Rich, A., & Casellas, D. (1994). Ascending myogenic autoregulation:
Interactions between tubuloglomerular feedback and myogenic mechanisms. Bulletin of
Mathematical Biology, 56(3), 391-410.
Moyna, N. M., & Thompson, P. D. (2004). The effect of physical activity on endothelial
function in man. Acta Physiologica Scandinavica, 180(2), 113-123.
Naylor, L. H., O'Driscoll, G., Fitzsimons, M., Arnolda, L. F., & Green, D. J. (2006).
Effects of training resumption on conduit arterial diameter in elite rowers. Medicine and
Science in Sports and Exercise, 38(1), 86-92.
Naylor, L. H., Weisbrod, C. J., O'Driscoll, G., & Green, D. J. (2005). Measuring peripheral resistance and conduit arterial structure in humans using doppler ultrasound.
Journal of Applied Physiology (Bethesda, Md.: 1985), 98(6), 2311-2315.
Nicpon-Marieb, E. (2004). Human anatomy & physiology (6th ed.). San Francisco: Benjamin Cummings.
Nordlander, M. I. (1989). Inhibition of vascular myogenic tone and reactivity by calcium
antagonists. Journal of Hypertension.Supplement : Official Journal of the International
Society of Hypertension, 7(4), S141-5; discussion S146.
Oida, K., Ebata, K., Kanehara, H., Suzuki, J., & Miyamori, I. (2003). Effect of cilostazol
on impaired vasodilatory response of the brachial artery to ischemia in smokers. Journal
of Atherosclerosis and Thrombosis, 10(2), 93-98.
Oluwole, B. O., McMIllen, M., & Sumpio, B. E. (1995). Endothelial cell control of
vasomotor tone. Annals of Vascular Surgery, 9(3), 293-301.