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Heikki Kyröläinen - One of the best experts on this subject based on the ideXlab platform.
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Effects of Exercise Intensity and duration on nocturnal heart rate variability and sleep quality
European Journal of Applied Physiology, 2012Co-Authors: Tero Myllymäki, Heikki Rusko, Heidi J. Syväoja, Tanja Juuti, Marja-liisa Kinnunen, Heikki KyröläinenAbstract:Acute physical Exercise may affect cardiac autonomic modulation hours or even days during the recovery phase. Although sleep is an essential recovery period, the information on nocturnal autonomic modulation indicated by heart rate variability (HRV) after different Exercises is mostly lacking. Therefore, this study investigated the effects of Exercise Intensity and duration on nocturnal HR, HRV, HR, and HRV-based relaxation, as well as on actigraphic and subjective sleep quality. Fourteen healthy male subjects (age 36 ± 4 years, maximal oxygen uptake 49 ± 4 ml/kg/min) performed five different running Exercises on separate occasions starting at 6 p.m. with HR guidance at home. The effect of Intensity was studied with 30 min of Exercises at intensities corresponding to HR level at 45% (easy), 60% (moderate) and 75% (vigorous) of their maximal oxygen uptake. The effect of duration was studied with 30, 60, and 90 min of moderate Exercises. Increased Exercise Intensity elevated nocturnal HR compared to control day ( p
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Effects of Exercise Intensity and duration on nocturnal heart rate variability and sleep quality
European Journal of Applied Physiology, 2011Co-Authors: Tero Myllymäki, Heikki Rusko, Heidi J. Syväoja, Tanja Juuti, Marja-liisa Kinnunen, Heikki KyröläinenAbstract:Acute physical Exercise may affect cardiac autonomic modulation hours or even days during the recovery phase. Although sleep is an essential recovery period, the information on nocturnal autonomic modulation indicated by heart rate variability (HRV) after different Exercises is mostly lacking. Therefore, this study investigated the effects of Exercise Intensity and duration on nocturnal HR, HRV, HR, and HRV-based relaxation, as well as on actigraphic and subjective sleep quality. Fourteen healthy male subjects (age 36 ± 4 years, maximal oxygen uptake 49 ± 4 ml/kg/min) performed five different running Exercises on separate occasions starting at 6 p.m. with HR guidance at home. The effect of Intensity was studied with 30 min of Exercises at intensities corresponding to HR level at 45% (easy), 60% (moderate) and 75% (vigorous) of their maximal oxygen uptake. The effect of duration was studied with 30, 60, and 90 min of moderate Exercises. Increased Exercise Intensity elevated nocturnal HR compared to control day (p < 0.001), but it did not affect nocturnal HRV. Nocturnal HR was greater after the day with 90- than 30- or 60-min Exercises (p < 0.01) or control day (p < 0.001). Nocturnal HRV was lower after the 90-min Exercise day compared to control day (p < 0.01). Neither Exercise Intensity nor duration had any impact on actigraphic or subjective sleep quality. The results suggest that increased Exercise Intensity and/or duration cause delayed recovery of nocturnal cardiac autonomic modulation, although long Exercise duration was needed to induce changes in nocturnal HRV. Increased Exercise Intensity or duration does not seem to disrupt sleep quality.
Glenn K Mcconell - One of the best experts on this subject based on the ideXlab platform.
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effect of Exercise Intensity on skeletal muscle ampk signaling in humans
Diabetes, 2003Co-Authors: Zhiping Chen, Terry J Stephens, Sid Murthy, Benedict J Canny, Mark Hargreaves, Lee A Witters, Bruce E Kemp, Glenn K McconellAbstract:The effect of Exercise Intensity on skeletal muscle AMP-activated protein kinase (AMPK) signaling and substrate metabolism was examined in eight men cycling for 20 min at each of three sequential intensities: low (40 ± 2% Vo2 peak), medium (59 ± 1% Vo2 peak), and high (79 ± 1% Vo2 peak). Muscle free AMP/ATP ratio only increased at the two higher Exercise intensities (P
Toby Mundel - One of the best experts on this subject based on the ideXlab platform.
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Skin temperature as a thermal controller of Exercise Intensity
European Journal of Applied Physiology, 2011Co-Authors: Zachary J. Schlader, Shona E. Simmons, Stephen R Stannard, Toby MundelAbstract:This study examined the role of skin temperature on self-selected Exercise Intensity (i.e., power output). Eight well-trained, male cyclists completed two 60 min self-paced cycling bouts during which they completed as much work as possible. Using a liquid-perfused suit, skin temperature ( T _Sk) was changed during the two trials such that T _Sk either started hot and was cooled (H to C) or started cold and was heated (C to H) throughout Exercise. Pre-Exercise core temperatures ( T _C) and heart rates (HR) were similar between trials, while T _Sk, thermal comfort and thermal sensation were higher in H to C. The change in T _Sk was similar in magnitude during the two trials. Work completed was greatest in C to H, which was attributed to a higher initial power output. T _C was similar between trials. HR was similar until 35 min had elapsed, after which it became lower in H to C. The perception of effort increased similarly between the two trials, while thermal comfort and thermal sensation generally reflected the changes observed in T _Sk. These results indicate that upon Exercise commencement T _Sk and the accompanying thermal perceptions are important inputs in the initial selection of Exercise Intensity.
Francis D Reardon - One of the best experts on this subject based on the ideXlab platform.
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can supine recovery mitigate the Exercise Intensity dependent attenuation of post Exercise heat loss responses
Applied Physiology Nutrition and Metabolism, 2008Co-Authors: Glen P Kenny, Daniel Gagnon, Natalie H Mcinnis, Shane W Journeay, Francis D ReardonAbstract:Cutaneous vascular conductance (CVC) and sweat rate are subject to non-thermal baroreflex-mediated attenuation post-Exercise. Various recovery modalities have been effective in attenuating these decreases in CVC and sweat rate post-Exercise. However, the interaction of recovery posture and preceding Exercise Intensity on post-Exercise thermoregulation remains unresolved. We evaluated the combined effect of supine recovery and Exercise Intensity on post-Exercise cardiovascular and thermal responses relative to an upright seated posture. Seven females performed 15 min of cycling ergometry at low- (LIE, 55% maximal oxygen consumption) or high-(HIE, 85% maximal oxygen consumption) Intensity followed by 60 min of recovery in either an upright seated or supine posture. Esophageal temperature, CVC, sweat rate, cardiac output, stroke volume, heart rate, total peripheral resistance, and mean arterial pressure (MAP) were measured at baseline, at end-Exercise, and at 2, 5, 12, 20, and every 10 min thereafter until t...
Mike Lambert - One of the best experts on this subject based on the ideXlab platform.
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methods of prescribing relative Exercise Intensity physiological and practical considerations
Sports Medicine, 2013Co-Authors: Theresa N Mann, Robert P Lamberts, Mike LambertAbstract:Exercise prescribed according to relative Intensity is a routine feature in the Exercise science literature and is intended to produce an approximately equivalent Exercise stress in individuals with different absolute Exercise capacities. The traditional approach has been to prescribe Exercise Intensity as a percentage of maximal oxygen uptake (VO2max) or maximum heart rate (HRmax) and these methods remain common in the literature. However, Exercise Intensity prescribed at a %VO2max or %HRmax does not necessarily place individuals at an equivalent Intensity above resting levels. Furthermore, some individuals may be above and others below metabolic thresholds such as the aerobic threshold (AerT) or anaerobic threshold (AnT) at the same %VO2max or %HRmax. For these reasons, some authors have recommended that Exercise Intensity be prescribed relative to oxygen consumption reserve (VO2R), heart rate reserve (HRR), the AerT, or the AnT rather than relative to VO2max or HRmax. The aim of this review was to compare the physiological and practical implications of using each of these methods of relative Exercise Intensity prescription for research trials or training sessions. It is well established that an Exercise bout at a fixed %VO2max or %HRmax may produce interindividual variation in blood lactate accumulation and a similar effect has been shown when relating Exercise Intensity to VO2R or HRR. Although individual variation in other markers of metabolic stress have seldom been reported, it is assumed that these responses would be similarly heterogeneous at a %VO2max, %HRmax, %VO2R, or %HRR of moderate-to-high Intensity. In contrast, Exercise prescribed relative to the AerT or AnT would be expected to produce less individual variation in metabolic responses and less individual variation in time to exhaustion at a constant Exercise Intensity. Furthermore, it would be expected that training prescribed relative to the AerT or AnT would provide a more homogenous training stimulus than training prescribed as a %VO2max. However, many of these theoretical advantages of threshold-related Exercise prescription have yet to be directly demonstrated. On a practical level, the use of threshold-related Exercise prescription has distinct disadvantages compared to the use of %VO2max or %HRmax. Thresholds determined from single incremental tests cannot be assumed to be accurate in all individuals without verification trials. Verification trials would involve two or three additional laboratory visits and would add considerably to the testing burden on both the participant and researcher. Threshold determination and verification would also involve blood lactate sampling, which is aversive to some participants and has a number of intrinsic and extrinsic sources of variation. Threshold measurements also tend to show higher day-to-day variation than VO2max or HRmax. In summary, each method of prescribing relative Exercise Intensity has both advantages and disadvantages when both theoretical and practical considerations are taken into account. It follows that the most appropriate method of relative Exercise Intensity prescription may vary with factors such as Exercise Intensity, number of participants, and participant characteristics. Considering a method’s limitations as well as advantages and increased reporting of individual Exercise responses will facilitate accurate interpretation of findings and help to identify areas for further study.