Consecutive days of cold water immersion: effects on cycling performance and heart rate variability

We investigated performance and heart rate (HR) variability (HRV) over consecutive days of cycling with post-exercise cold water immersion (CWI) or passive recovery (PAS). In a crossover design, 11 cyclists completed two separate 3-day training blocks (120 min cycling per day, 66 maximal sprints, 9 min time trialling [TT]), followed by 2 days of recovery-based training. The cyclists recovered from each training session by standing in cold water (10 °C) or at room temperature (27 °C) for 5 min. Mean power for sprints, total TT work and HR were assessed during each session. Resting vagal-HRV (natural logarithm of square-root of mean squared differences of successive R-R intervals; ln rMSSD) was assessed after exercise, after the recovery intervention, during sleep and upon waking. CWI allowed better maintenance of mean sprint power (between-trial difference [90 % confidence limits] +12.4 % [5.9; 18.9]), cadence (+2.0 % [0.6; 3.5]), and mean HR during exercise (+1.6 % [0.0; 3.2]) compared with PAS. ln rMSSD immediately following CWI was higher (+144 % [92; 211]) compared with PAS. There was no difference between the trials in TT performance (-0.2 % [-3.5; 3.0]) or waking ln rMSSD (-1.2 % [-5.9; 3.4]). CWI helps to maintain sprint performance during consecutive days of training, whereas its effects on vagal-HRV vary over time and depend on prior exercise intensity

Facilitating adherence to physical activity: exercise professionals' experiences of the National Exercise Referral Scheme in Wales. A qualitative study

<p>Abstract</p> <p>Background</p> <p>Although implementers' experiences of exercise referral schemes (ERS) may provide valuable insights into how their reach and effectiveness might be improved, most qualitative research has included only views of patients. This paper explores exercise professionals' experiences of engaging diverse clinical populations in an ERS, and emergence of local practices to support uptake and adherence in the National Exercise Referral Scheme (NERS) in Wales.</p> <p>Methods</p> <p>Thirty-eight exercise professionals involved in the delivery of NERS in 12 local health board (LHB) areas in Wales took part in a semi-structured telephone interview. Thematic analysis was conducted.</p> <p>Results</p> <p>Professionals' accounts offered insights into how perceived needs and responses to NERS varied by patient characteristics. Adherence was described as more likely where the patient sought referral from a health professional rather than being advised to attend. Hence, professionals sometimes described a need for the referral process to identify patients for whom change was already internally motivated. In addition, mental health patients were seen as facing additional barriers, such as increased anxieties about the exercise environment. Professionals described their role as involving helping patients to overcome anxieties about the exercise environment, whilst providing education and interpersonal support to assist patients' confidence and motivation. However, some concerns were raised regarding the levels of support that the professional should offer whilst avoiding dependence. Patient-only group activities were described as supporting adherence by creating an empathic environment, social support and modelling. Furthermore, effectively fostering social support networks was identified as a key mechanism for reducing dependence and maintaining changes in the longer term.</p> <p>Conclusions</p> <p>Whether ERS should identify motivated patients, or incorporate activities to support internalisation of motivation amongst less motivated patients deserves attention. As well as providing the knowledge to advise patients on how to exercise safely given their conditions, professionals' training should focus on providing the skills to meet the interpersonal support needs of patients, particularly where ERS are used as a means of improving mental health outcomes. The effectiveness of emerging activities, such as post-scheme maintenance classes, in fostering long-term social networks supportive of physical activity deserve attention.</p> <p>Trial registration</p> <p>Current Controlled Trials: <a href="http://www.controlled-trials.com/ISRCTN47680448">ISRCTN47680448</a></p

Cardiac parasympathetic reactivation following exercise: implications for training prescription

The objective of exercise training is to initiate desirable physiological adaptations that ultimately enhance physical work capacity. Optimal training prescription requires an individualized approach, with an appropriate balance of training stimulus and recovery and optimal periodization. Recovery from exercise involves integrated physiological responses. The cardiovascular system plays a fundamental role in facilitating many of these responses, including thermoregulation and delivery/removal of nutrients and waste products. As a marker of cardiovascular recovery, cardiac parasympathetic reactivation following a training session is highly individualized. It appears to parallel the acute/intermediate recovery of the thermoregulatory and vascular systems, as described by the supercompensation theory. The physiological mechanisms underlying cardiac parasympathetic reactivation are not completely understood. However, changes in cardiac autonomic activity may provide a proxy measure of the changes in autonomic input into organs and (by default) the blood flow requirements to restore homeostasis. Metaboreflex stimulation (e.g. muscle and blood acidosis) is likely a key determinant of parasympathetic reactivation in the short term (0–90 min post-exercise), whereas baroreflex stimulation (e.g. exercise-induced changes in plasma volume) probably mediates parasympathetic reactivation in the intermediate term (1–48 h post-exercise). Cardiac parasympathetic reactivation does not appear to coincide with the recovery of all physiological systems (e.g. energy stores or the neuromuscular system). However, this may reflect the limited data currently available on parasympathetic reactivation following strength/resistance-based exercise of variable intensity. In this review, we quantitatively analyse post-exercise cardiac parasympathetic reactivation in athletes and healthy individuals following aerobic exercise, with respect to exercise intensity and duration, and fitness/training status. Our results demonstrate that the time required for complete cardiac autonomic recovery after a single aerobic-based training session is up to 24 h following low-intensity exercise, 24–48 h following threshold-intensity exercise and at least 48 h following high-intensity exercise. Based on limited data, exercise duration is unlikely to be the greatest determinant of cardiac parasympathetic reactivation. Cardiac autonomic recovery occurs more rapidly in individuals with greater aerobic fitness. Our data lend support to the concept that in conjunction with daily training logs, data on cardiac parasympathetic activity are useful for individualizing training programmes. In the final sections of this review, we provide recommendations for structuring training microcycles with reference to cardiac parasympathetic recovery kinetics. Ultimately, coaches should structure training programmes tailored to the unique recovery kinetics of each individual