The effect of a high intensity interval training program on health-related outcomes in older adults

Nieuwoudt, Sharne (2015-12)

Thesis (MSc)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: Low levels of regular physical activity in older adults may lead to accelerated declines in overall health and functional capacity. Moderate continuous aerobic training (MCAT) has generally been recommended to combat the prevalence of lifestyle diseases in older adults, however adherence rates to this type of training are low, which necessitates the need for a viable alternative. High intensity interval training (HIIT) has been successfully implemented in young and clinical populations, yet there is limited evidence that advocates the use of HIIT in older adults to attain health benefits. Thus, the primary aim of this study was to determine the effect of HIIT on health-related outcomes in older adults. Twenty four sedentary older adults (age 62.8 ± 6.5 years; 37.3 ± 7.6 % body fat) volunteered for the 16 week HIIT and MCAT intervention. Participants were randomly assigned into 2 experimental groups: HIIT or MCAT. HIIT consisted of 4 stages of 4 minutes treadmill running at 90-95% of age predicted maximum heart rate (APMHR) with 3 minutes of active recovery between intervals. MCAT consisted of treadmill walking for 47 minutes at 70-75% of APMHR. The participants were tested for body composition, insulin resistance, blood lipids, functional capacity, cardiorespiratory fitness and quality of life, pre and post intervention. The pre-post intra-group changes were compared using paired t-tests and the magnitude of differences between groups was calculated using Cohen’s effect sizes. In addition the time x group interaction effects between HIIT and MCAT were calculated using 2x2 ANOVA. Both HIIT and MCAT elicited significant improvements in body fat percentage (HIIT: 1.9% vs MCAT: 2.2%), sagittal abdominal diameter (HIIT: 1.7cm vs MCAT: 1.6cm), waist circumference (HIIT: 4.1cm vs MCAT: 4.4cm) and hip circumference (HIIT: 5cm vs MCAT: 5.1cm) (p < 0.05). In addition, HIIT significantly improved fasting plasma glucose (HIIT: 0.3mmol/l vs MCAT: 0.1mmol/l) and cardiorespiratory fitness (HIIT: 7.6ml/kg/min vs MCAT: 1.8ml/kg/min) relative to MCAT (p < 0.05). Although not statistically significant, HIIT also exerted a greater practically significant improvement on the lipid profile and functional capacity relative to MCAT (ES = 0.41, 0.30 respectively). In contrast, MCAT succeeded in improving quality of life to a greater extent relative to HIIT, especially with regards to bodily pain (ES = 0.64). These results demonstrate that HIIT is a viable, tolerable and beneficial form of exercise in older adults. Although both HIIT and MCAT are able to significantly improve body composition, HIIT had a greater practically significant effect on insulin resistance, functional capacity and cardiorespiratory fitness relative to MCAT in older adults. These benefits translate into a reduced cardiovascular disease risk as well as an improvement in activities of daily living. Despite HIIT inducing a greater amount of bodily pain in participants, HIIT still elicited favourable changes in health outcomes.

AFRIKAANSE OPSOMMING: Lae vlakke van gereelde fisieke aktiwiteit by ouer volwassenes kan tot versnelde agteruitgang in algehele gesondheid en in funksionele kapasiteit lei. Matige aaneenlopende aërobiese oefening (in Engels moderate continuous aerobic training of MCAT) word tans oor die algemeen aanbeveel om die voorkoms van lewenstylsiektes by ouer volwassenes te beveg, maar handhawingskoerse vir hierdie soort oefening is laag, wat ’n soeke na ’n lewensvatbare alternatief noodsaak. Hoë-intensiteit-interval-oefening (in Engels high intensity interval training of HIIT) is wel reeds suksesvol in jong en kliniese populasies geïmplementeer, maar daar is slegs beperkte bewyse om die gebruik van HIIT vir die verkryging van gesondheidsvoordele by ouer volwassenes voor te staan. Daarom was die primêre doel van hierdie studie om die uitwerking van hoë-intensiteit-interval-oefening op gesondheidsverwante uitkomste by ouer volwassenes te bepaal. Vier-en-twintig onaktiewe ouer volwassenes (ouderdom 62.8 ± 6.5 jaar; liggaamsvet 37.3 ± 7.6%) het hulself vrywillig verklaar om aan ’n 16-weeklange HIIT en MCAT intervensie deel te neem. Deelnemers is ewekansig in twee eksperimentele groepe verdeel: HIIT of MCAT. HIIT het bestaan uit vier fases van vier minute hardloop op ’n trapmeul teen 90-95% van ouderdom-voorspelde maksimum hartspoedtempo (in Engels age predicted maximum heart rate of APMHR) met drie minute se aktiewe herstel tussen intervalle. MCAT het bestaan daaruit om vir 47 minute op ’n trapmeul te loop teen 70-75% van APMHR. Die deelnemers is getoets vir liggaamsamestelling, insulien weerstandigheid, bloedlipiede, funksionele kapasiteit, kardiorespiratoriese fiksheid en lewensgehalte, voor en na die intervensie. Die pre- en post-intragroep-veranderinge is vergelyk met die gebruik van gepaarde t-toetse en die grootte van verskille tussen groepe is bereken deur Cohen se effekgroottes te gebruik. Die tyd x groep interaksie effek tussen HIIT en MCAT is addisioneel bereken met 2x2 ANOVA. Beide HIIT en MCAT het tot betekenisvolle verbeterings in liggaamsvetpersentasie (HIIT: 1.9% vs MCAT: 2.2%), sagitale abdominale deursnit (HIIT: 1.7cm vs MCAT: 1.6cm), middelomtrek (HIIT: 4.1cm vs MCAT: 4.4cm) en heupomtrek (HIIT: 5cm vs MCAT: 5.1cm) (p < 0.05) gelei. Verder het HIIT, relatief tot MCAT, vastende-plasmaglukose (HIIT: 0.3mmol/l vs MCAT: 0.1mmol/l) en kardiorespiratoriese fiksheid (HIIT: 7.6ml/kg/min vs MCAT: 1.8ml/kg/min) (p < 0.05) betekenisvol verbeter. Hoewel nie statisties betekenisvol nie, het HIIT ook ’n sterker praktiese betekenisvolle verbetering van die lipiedprofiel en funksionele kapasiteit relatief tot MCAT (ES = 0.41, 0.30 onderskeidelik) gehad. Hierteenoor het MCAT wel daarin geslaag om lewensgehalte tot ’n groter mate relatief tot HIIT te verbeter, veral ten opsigte van liggaamspyn (ES = 0.64). Hierdie resultate demonstreer dat HIIT ’n lewensvatbare, hanteerbare en voordelige vorm van oefening vir ouer volwassenes is. Hoewel beide HIIT en MCAT in staat is om liggaamsamestelling betekenisvol te verbeter, het HIIT, relatief tot MCAT, ’n groter prakties betekenisvolle uitwerking op insulien weerstandigheid, funksionele kapasiteit en kardiorespiratoriese fiksheid in ouer volwassenes. Hierdie voordele word omgeskakel in ’n verminderde risiko vir kardiovaskulêre siekte, sowel as in ’n verbetering in aktiwiteite van die daaglikse lewe. Ten spyte daarvan dat HIIT meer liggaamspyn in deelnemers veroorsaak, lei HIIT steeds tot gunstige veranderinge in gesondheidsuitkomstes.

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