Heart rate variability in middle-aged sprint and endurance athletes

Purpose: Considerable interindividual heterogeneity has been observed in endurance performance responses following induction of a ketogenic diet (KD). It is plausible that a physiological stress response in the period following the dramatic dietary shift associated with transition to a KD may explain this heterogeneity. Methods: In a randomized, crossover study design, 8 trained male runners completed an incremental exercise test and ran to exhaustion at 70%VO2max before and after a 31-day rigorously controlled habitual diet or KD intervention, and recorded heart rate variability (root mean square of the sum of successive differences in R–R intervals [rMSSD]) upon waking each morning along with the recovery–stress questionnaire for athletes each week. Data were analyzed using linear mixed models. Results: A significant reduction in rMSSD was observed in the KD (−9.77 [4.03] ms, P = .02), along with an increase in day-to-day variability in rMSSD (2.1% [1.0%], P = .03). The reduction in rMSSD in the KD for the subgroup of individuals exhibiting impaired exercise capacity following induction of the KD approached significance (Δ −22 [15] ms, P = .06, N = 4); whereas no effect was observed in those who exhibited unchanged exercise capacity (Δ 5 [18] ms, P = .61, N = 4). No main effects were observed for recovery–stress questionnaire for athletes. Conclusions: Our data suggest those working with endurance athletes transitioning onto a KD may consider using noninvasive, inexpensive resting heart rate variability measures to gain individual-level insights into the likely short-term effects on exercise capacity.

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Middle-aged endurance athletes exhibit lower cerebrovascular impedance than sedentary peers

Journal of Applied Physiology ◽

10.1152/japplphysiol.00239.2020 ◽

2020 ◽

Vol 129 (2) ◽

pp. 335-342

Author(s):

Jun Sugawara ◽

Tsubasa Tomoto ◽

Justin Repshas ◽

Rong Zhang ◽

Takashi Tarumi

Keyword(s):

Heart Rate ◽

Endurance Training ◽

Brain Perfusion ◽

Endurance Athletes ◽

Middle Aged ◽

Harmonic Oscillations ◽

Middle Aged Adults

Impedance modulus in the range of first harmonic oscillations (0.78–1.56 Hz), which reflects heart rate at rest, was lower in middle-aged endurance athletes than in age-matched sedentary peers and was similar to young individuals. Prolonged endurance training is associated with the improved cerebrovascular dampening function in middle-aged adults. Lower cerebrovascular impedance modulus may contribute to maintaining brain perfusion in midlife.

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Determinants and interindividual variation of R-R interval dynamics in healthy middle-aged subjects

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.280.3.h1400 ◽

2001 ◽

Vol 280 (3) ◽

pp. H1400-H1406 ◽

Cited By ~ 42

Author(s):

Sirkku M. Pikkujämsä ◽

Timo H. Mäkikallio ◽

K. E. Juhani Airaksinen ◽

Heikki V. Huikuri

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Supine Position ◽

Population Sample ◽

Interindividual Variation ◽

Sitting Position ◽

Middle Aged ◽

Complexity Measures ◽

Rate Behavior ◽

Z Value

Determinants and intersubject variations of fractal and complexity measures of R-R interval variability were studied in a random population of 200 healthy middle-aged women (age 51 ± 6 yr) and 189 men (age 50 ± 6 yr) during controlled conditions in the supine and sitting positions. The short-term fractal exponent (α1) was lower in women than men in both the supine (1.18 ± 0.20 vs. 1.12 ± 0.17, P < 0.01) and sitting position ( P < 0.001). Approximate entropy (ApEn), a measure of complexity, was higher in women in the sitting position (1.16 ± 0.17 vs. 1.07 ± 0.19, P < 0.001), but no gender-related differences were observed in ApEn in the supine position. Fractal and complexity measures were not related to any other demographic, laboratory, or lifestyle factors. Intersubject variations in a fractal measure, α1 (e.g., 1.15 ± 0.20 in the supine position, z value 1.24, not significant), and in a complexity measure, ApEn (e.g., 1.14 ± 0.18 in the supine position, z value 1.44, not significant), were generally smaller and more normally distributed than the variations in the traditional measures of heart rate variability (e.g., standard deviation of R-R intervals 49 ± 21 ms in the supine position, z value 2.53, P < 0.001). These results in a large random population sample show that healthy subjects express relatively little interindividual variation in the fractal and complexity measures of heart rate behavior and, unlike the traditional measures of heart rate variability, they are not related to lifestyle, metabolic, or demographic variables. However, subtle gender-related differences are also present in fractal and complexity measures of heart rate behavior.

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Relationship Between Morning Heart Rate Variability and Creatine Kinase Response During Intensified Training in Recreational Endurance Athletes

Frontiers in Physiology ◽

10.3389/fphys.2018.01267 ◽

2018 ◽

Vol 9 ◽

Cited By ~ 2

Author(s):

Matthias Weippert ◽

Martin Behrens ◽

Anett Mau-Moeller ◽

Sven Bruhn ◽

Kristin Behrens

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Creatine Kinase ◽

Endurance Athletes

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Heat Stress Training Camps for Endurance Sport: A Descriptive Case Study of Successful Monitoring in 2 Ironman Triathletes

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2019-0096 ◽

2020 ◽

Vol 15 (1) ◽

pp. 146-150

Author(s):

Ed Maunder ◽

Andrew E. Kilding ◽

Christopher J. Stevens ◽

Daniel J. Plews

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Heat Stress ◽

Well Being ◽

Self Report ◽

Endurance Athletes ◽

Resting Heart Rate ◽

Resting Heart Rate Variability ◽

Stress Training

A common practice among endurance athletes is to purposefully train in hot environments during a “heat stress camp.” However, combined exercise-heat stress poses threats to athlete well-being, and therefore, heat stress training has the potential to induce maladaptation. This case study describes the monitoring strategies used in a successful 3-week heat stress camp undertaken by 2 elite Ironman triathletes, namely resting heart rate variability, self-report well-being, and careful prescription of training based on previously collected physiological data. Despite the added heat stress, training volume very likely increased in both athletes, and training load very likely increased in one of the athletes, while resting heart rate variability and self-report well-being were maintained. There was also some evidence of favorable metabolic changes during routine laboratory testing following the camp. The authors therefore recommend that practitioners working with endurance athletes embarking on a heat stress training camp consider using the simple strategies employed in the present case study to reduce the risk of maladaptation and nonfunctional overreaching.

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