Effects of heavy strength training on acute blood pressure, blood pressure at rest and after exercise in healthy male volunteers

Høyt blodtrykk (BT), også benevnt hypertensjon (HT) er den viktigste modifiserbare risikofaktoren for utvikling av kardiovaskulære sykdommer. Det antas at minst 25 % av befolkningen i både Norden og i USA lider av HT. Vårt mål med denne studien var å undersøke om tung ST med vekt på god pusteteknikk og konsentriske kontraksjoner med kort varighet og få repetisjoner (3 av 5RM - 3REP), kunne gjennomføres med lavere akutte BT-økninger men med tilsvarende PEH-fase som ved tilsvarende ST med 5RM (5REP). Syv normotensive mannlige idrettsaktive studenter (23,8 ± 1,4 år) gjennomførte hele studien. Funnene fra denne studien demonstrerer at tung ST med få repetisjoner (5RM) kan utføres uten at det akutte BT øker til ekstreme verdier, videre at så lite som 72 sekunders effektiv ST (3REP) kan indusere PEH med varighet på en time

Seasonal variations in physical activity among Norwegian elementary school children in Arctic regions

The aim of this study was to measure seasonal variations in physical activity (PA) during Polar Nights (PN) and Polar Days (PD) among elementary school children in the Arctic regions of Norway. One hundred and seventy-eight schoolchildren from 1st, 3rd, 5th and 7th grade participated in the study. Physical activity was measured for seven consecutive days with an ActiGraph GT3X-BT accelerometer and is expressed as total PA incounts per minute (cpm) and moderate-to-vigorous activity (MVPA) (min∙day−1). During PN, 51% of boys and 33% of girls met the PA recommendations, whereas 36% of boys and 34% of girls met the recommendations during PD. Time spent doing MVPA did not differ between the two seasons (all p ≥ 0.073). Overall, the children accumulated 613 ±154 cpm during PN, which was lower than during PD 704 ± 269 cpm, p < 0.001). A larger proportion of boys than girls met the PA recommendations during PN compared with PD. Our findings did not show any clear seasonal variation for MVPA or total PA among children,except for some differences within sexes in different grades. This study indicates that interventions aimed at increasing PA should be implemented throughout the year in the Arctic regions

Ski skating race technique-effect of long distance cross-country ski racing on choice of skating technique in moderate uphill terrain

The aim of this study was to investigate the effect of prolonged ski racing using skating style on technique choice in a transition section among female and male high-level skiers. Fifty three national-to-elite level skiers (20 females: 26.7 \ub1 4.8 years, 167.0 \ub1 6.5 m, 61.0 \ub1 5.1 kg, and 75.5 \ub1 68.8 FIS points; 33 males: 25.2 \ub1 3.5 years, 179.0 \ub1 5.2 cm, 73.1 \ub1 5.7 kg, and 73.7 \ub1 63.2 FIS points) were video recorded along a flat-to-uphill transition section of a course during the 30-km (females) and 50-km (males) races at the 2018 Norwegian National Championships. Across laps, section speeds decreased (P &lt; 0.001) in all skiers, with the best-ranked skiers faster than the lowest-ranked (P &lt; 0.001), and males faster than females in the first and middle laps. Section speed within each lap was associated with race performance (r = 0.76-0.86, P &lt; 0.001 in females and r = 0.87-0.89, P &lt; 0.001 in males). The prevalence of Gear 2 (G2) increased, while Gear 3 (G3) use decreased (both P &lt; 0.001) across the subsequent laps, with females preferring G2 more than males in lap one (P = 0.027). In long-distance skate-style skiing, transition performance is representative of race performance and skiers decrease the use of the often-faster G3 technique while increasing the use of the slower G2 technique due to prolonged exercise. Especially female skiers should consider adding some flat-to-uphill G3 practice into established training, specifically early in the session before fatigue may occur

Physical activity and the structure and function of the left side of the heart

Current knowledge about the relationship between exercise and cardiac remodelling is mostly based on studies of athletes. Little is known about cardiac adaptations to moderate doses of exercise in the general adult and elderly population, and whether exercise-induced cardiac remodelling is a benign physiological adaption of exercise or part of a pathophysiological mechanism. The main objective of this thesis was to study the association between physical activity (PA) and the structure and function of the left side of the heart. Also, we wanted to explore if exercise-related left atrial (LA) remodelling was associated with adverse cardiac alterations and increased risk of incident atrial fibrillation (AF). In paper I, we applied a longitudinal design with repeated measures of self-reported PA and echocardiographic structural and functional data. In paper II, we applied a cross-sectional design to investigate the association between device-based PA and LA size. In paper III, we applied a prospective design to investigate the association between self-reported PA, LA size, and risk of AF. The main findings of this thesis are that exercise-induced cardiac remodelling also occurs with moderate levels of habitual PA, and not only in endurance-trained athletes. Moreover, our results indicate that exercise-induced LA remodelling is a benign physiological adaptation to exercise, without being associated with reduced left ventricular (LV) diastolic function or increased risk of incident AF. Higher levels of PA were associated with increased LA size in general, and increased LV size in females. However, no change in pump function or atrioventricular ratio at rest was observed with higher levels of PA. Moreover, moderate levels of habitual PA were associated with reduced risk of AF, and active individuals with LA enlargement did not have higher risk of AF than either active or inactive with normal LA size.Nåværende kunnskap om sammenhengen mellom trening og hjerteremodellering er for det meste basert på studier av idrettsutøvere. Lite er kjent om hjertetilpasninger til moderate doser trening i den generelle voksne- og eldre befolkningen, og om treningsindusert hjertemodellering er en normal fysiologisk tilpasning til trening, eller en del av en patofysiologisk mekanisme. Dessuten er sammenhengen mellom fysisk aktivitet (FA), hjerteremodellering, og langtidsrisiko for atrieflimmer (AF) kompleks og representerer et kunskapshull, spesielt i den generelle voksen og eldre befolkningen. Hovedmålet med denne avhandlingen var å studere sammenhengen mellom FA og hjertets venstre sides struktur og funksjon. Vi ønsket også å undersøke om treningsrelatert remodellering av venstre atrium (VA) var assosiert med uønskede hjerteendringer og økt risiko for AF. I artikkel I brukte vi et longitudinelt design med gjentatte mål av selvrapportert FA og ekkokardiografiske strukturelle og funksjonelle data. I artikkel II brukte vi et tverrsnittsdesign for å undersøke sammenhengen mellom monitormålt FA og VA-størrelse. I artikkel III brukte vi et prospektivt design for å undersøke sammenhengen mellom selvrapportert FA, VA-størrelse og risiko for AF. Hovedfunnene i denne avhandlingen er at treningsindusert hjerteremodellering også forekommer ved moderate nivåer alminnelig FA, og ikke bare hos utholdehetsutøvere. Dessuten indikerer resultatene våre at treningsindusert VA-remodellering er en normal fysiologisk tilpasning til trening, uten å være assosiert med redusert venstre ventrikkel (VV) diastolisk funksjon eller økt risiko for insidens av AF. Høyere nivåer FA var assosiert med økt VA-størrelse generelt, og økt VVstørrelse hos kvinner. Imidlertid ble ingen endring i pumpefunksjon aller atrioventrikulært forhold i hvile observert ved høyere nivåer FA. Moderate nivåer FA var assosiert med redusert risiko for AF, og aktive individer med VA-forstørrelse hadde ikke høyere risiko for AF enn hverken aktive- eller inaktive med normal VA-størrelse

Effects of heavy strength training on acute blood pressure, blood pressure at rest and after exercise in healthy male volunteers

Høyt blodtrykk (BT), også benevnt hypertensjon (HT) er den viktigste modifiserbare risikofaktoren for utvikling av kardiovaskulære sykdommer. Det antas at minst 25 % av befolkningen i både Norden og i USA lider av HT. Vårt mål med denne studien var å undersøke om tung ST med vekt på god pusteteknikk og konsentriske kontraksjoner med kort varighet og få repetisjoner (3 av 5RM - 3REP), kunne gjennomføres med lavere akutte BT-økninger men med tilsvarende PEH-fase som ved tilsvarende ST med 5RM (5REP). Syv normotensive mannlige idrettsaktive studenter (23,8 ± 1,4 år) gjennomførte hele studien. Funnene fra denne studien demonstrerer at tung ST med få repetisjoner (5RM) kan utføres uten at det akutte BT øker til ekstreme verdier, videre at så lite som 72 sekunders effektiv ST (3REP) kan indusere PEH med varighet på en time

Intra‐arterial blood pressure traits during and after heavy resistance exercise in healthy males

This randomized within‐subjects crossover‐designed study evaluated intra‐arterial blood pressure (BP) traits in seven healthy males (24 ± 1 years) during heavy resistance exercise (HRE) to failure (10 × 5 repetitions, 5RES) and not to failure (10 × 3 repetitions, 3RES), both at 5RM load. By combining few repetitions, avoidance of Valsalva maneuver, and restricting the duration of each contraction, we hypothesized (a) that HRE could be performed without acute excessive elevated BP; (b) a dose relationship regarding acute BP elevation following 5RES versus 3RES; and (c) both modes of HRE to induce post‐exercise hypotension (PEH). BP was measured before, during, and throughout 90 minutes post‐exercise. Systolic BP and mean arterial pressure decreased during 3RES (P P P < .01). Documented by continuous intra‐arterial BP monitoring, this study demonstrates that HRE can be performed without acute excessive elevated BP during exercise, but still induce PEH. These novel results are important, as they may pave way for future studies utilizing HRE in patients where avoidance of excessive elevated BP is important

Longitudinal Associations Between Cumulative Physical Activity and Change in Structure and Function of the Left Side of the Heart: The Tromsø Study 2007–2016

Background Current knowledge about the relationship between physical activity (PA) and cardiac remodeling is mainly derived from cross-sectional studies of athletes, and there is a knowledge gap of this association in the general adult and elderly population. Therefore, we aimed to explore the longitudinal association between cumulative PA and change in cardiac structure and function in a general adult and elderly population. Methods This longitudinal study includes 594 participants from the sixth (Tromsø6, 2007–08) and seventh (Tromsø7, 2015–16) survey of the Tromsø Study. Cardiac structure and function were assessed by echocardiography at two time points, and PA was self-reported by questionnaire at both time points. PA volume was expressed as cumulative PA (Low, Moderate, and Hard) and the association with left atrial (LA) and left ventricular (LV) structure and function was assessed using ANCOVA. Results Overall, LA diameter index (LADi) increased significantly more in Hard compared to Moderate PA (+0.08 cm/m 2 , 95% CI 0.01–0.15, p = 0.020) from Tromsø6 to Tromsø7. When stratified by sex or age, higher levels of cumulative PA were associated with increased LADi in males and in participants &amp;lt;65 years only. Indexed LV mass (LVMi) increased significantly more in Moderate than in Low PA (+3.9 g/m 2.7 , 95% CI 0.23–7.57, p = 0.037). When stratified by sex or age, these changes in LVMi and indexed LV diameter (LVDi) were only significant in females. No significant associations were observed between cumulative PA and change in relative wall thickness, E/e' ratio, e' velocity, LV ejection fraction, and LADi/LVDi ratio. Conclusion Higher levels of cumulative PA were associated with increased LADi in males and participants &amp;lt;65 years, and with increased LVMi and LVDi in females. Despite cardiac chamber enlargement, the pump function of the heart did not change with higher levels of PA, and the atrioventricular ratio was unchanged. Our results indicate that cardiac chamber enlargement is a physiological response to PA

Associations between physical activity, left atrial size and incident atrial fibrillation: the Tromsø Study 1994–2016

Aims Left atrial (LA) enlargement is an independent risk factor for atrial fibrillation (AF). Interestingly, some athletes have increased risk of AF, which may be linked to LA enlargement; however, little is known about the relationship between LA enlargement and AF risk at moderate-level physical activity (PA). We aimed to explore the associations between PA, LA size and risk of incident AF, and if PA can attenuate the risk of AF with LA enlargement. Methods This prospective study followed 2479 participants (52.4% female), free from known cardiac pathology, for median 20.2 years. Participants were followed up for hospital-diagnosed AF, confirmed by electrocardiography, from 1994-95 through 2016. At baseline, LA size was evaluated by anteroposterior LA diameter, and PA was self-reported by questionnaire. Results We observed a U-shaped relationship between PA and AF, and moderately active had 32% lower AF risk than inactive (HR adjusted 0.68, 95% CI 0.50 to 0.93). Participants with LA enlargement had 38% higher AF risk compared with participants with normal LA size (HR adjusted 1.38, 95% CI 1.12 to 1.69). However, the increased AF risk with LA enlargement was attenuated by PA; compared with inactive participants with LA enlargement, the AF risk was 45% lower among active with LA enlargement (HR adjusted 0.55, 95% CI 0.39 to 0.79). AF risk in active participants with LA enlargement did not differ from active with normal LA size. These patterns were observed in both men and women, and in participants over/under 65 years. Conclusion Moderate PA was associated with reduced AF risk, and PA attenuated the increased risk of AF with LA enlargement in both men and women and all age groups