High heart rates in hunting harbour porpoises

The impressive breath-hold capabilities of marine mammals are facilitated by both enhanced O 2 stores and reductions in the rate of O 2 consumption via peripheral vasoconstriction and bradycardia, called the dive response. Many studies have focused on the extreme role of the dive response in maximizing dive duration in marine mammals, but few have addressed how these adjustments may compromise the capability to hunt, digest and thermoregulate during routine dives. Here, we use DTAGs, which record heart rate together with foraging and movement behaviour, to investigate how O 2 management is balanced between the need to dive and forage in five wild harbour porpoises that hunt thousands of small prey daily during continuous shallow diving. Dive heart rates were moderate (median minimum 47–69 bpm) and relatively stable across dive types, dive duration (0.5–3.3 min) and activity. A moderate dive response, allowing for some perfusion of peripheral tissues, may be essential for fuelling the high field metabolic rates required to maintain body temperature and support digestion during diving in these small, continuously feeding cetaceans. Thus, despite having the capacity to prolong dives via a strong dive response, for these shallow-diving cetaceans, it appears to be more efficient to maintain circulation while diving: extreme heart rate gymnastics are for deep dives and emergencies, not everyday use.

Heart rate variability—study in futsal athletes

Background The practice of high perfomance sports leads to alterations of the autonomic nervous system (ANS). The study of heart rate variability (HRV) resorting to the electrocardiogram (ECG) is a practical, efficient and non invasive tool that allows the monitorization of the cardiac-autonomic function in high perfomance athletes, exposing the physiological adaptations to repeated and intense physical exercise. To evaluate the resting heart rate variability of futsal players resorting to the electrocardiogram during the pre-season and competitive season. Methods The sample used in this study was composed of fifteen male futsal athletes, subjected to a resting electrocardiogram in supine position with the duration of 6 minutes, at two different moments. Results From the first to the second record heart rate variability, it was observed a significant decrease in heart rate from 66.53 ± 10.39 bpm to 61.50 ± 11.14 bpm (P < 0.05) and the indexes related to the activity of the parasympathetic nervous system (PNS), RMSSD, pNN50, HFnu did not present statistical significance (P > 0.05) despite the verified increased of absolute values from the first to the second evaluation. Conclusions We were able to observe a decrease in heart rate (HR), as well as, a tendency for elevated parasympathetic indexes and a vagal predominance from the first to the second moment of evaluation. The monitorization of heart rate variability can be useful to identify adaptations to competitive loads and, thus, planning adequate training loads for each athlete, avoiding the occurrence of lesions and fatigue and allowing an improvement in performance.

The Interplay Between Chamber Musicians During Two Public Performances of the Same Piece: A Novel Methodology Using the Concept of “Flow”

The purpose of the study is to explore a new research methodology that will improve our understanding of “flow” through indicators of physiological and qualitative state. We examine indicators of “flow” experienced by musicians of a youth string quartet, two women (25, 29) and two men (23, 24). Electrocardiogram (ECG) equipment was used to record heart rate variability (HRV) data throughout the four movements in one and the same quartet performed during two concerts. Individual physiological indicators of flow were supplemented by assessments of group “state flow” (means from standardized questionnaires) and a group interview in which the musicians provided qualitative data. A matrix was constructed for the characterization of different kinds of demands in the written music in each one of the four movements for each one of the musicians. HRV derived from ECG data showed non-significant trends for group state flow across the eight musical episodes. Individual-level analysis showed that compared to the other players the first violin player had the highest mean heart rate and the lowest increase in high frequency (HF) power in HRV during this particular movement, particularly during the second concert. The qualitative data illustrated how an interplay of synchronized social interactions between this player and their colleagues during the musical performance was associated with a feeling of group state flow and served to support the first violinist. The case illustrates that the proposed mixed methodology drawing on physiological and qualitative data, has the potential to provide meaningful information about experiences of a flow state, both at individual and group levels. Applications in future research are possible.

An Analysis of Warm-Up Strategies at a Cross-Country Skiing National Championship

Purpose: To provide a descriptive analysis of the warm-up (WU) strategies employed by cross-country skiers prior to distance and sprint competitions at a national championship and to compare the skiers’ planned and executed WUs prior to the respective competitions. Methods: Twenty-one national- and international-level skiers (11 women and 10 men) submitted WU plans prior to the distance and sprint competitions, and after the competitions, reported any deviations from the plans. Skiers used personal monitors to record heart rate (HR) during WU, races, and cooldown. Quantitative statistical analyses were conducted on WU durations, durations in HR-derived intensity zones, and WU loads. Qualitative analyses were conducted on skiers’ WU plans and their reasons for deviating from the plans. Results: Skiers’ planned WUs were similar in content and planned time in HR-derived intensity zones for both the distance and sprint competitions. However, 45% of the women and 20% of the men reported that their WU was not carried out as planned, with reasons detailed as being due to incorrect intensities and running out of time. WU activities including skiing across variable terrain, muscle-potentiating exercises, and heat-maintenance strategies were missing from the skiers’ planned routines. Conclusions: Skiers favored a long, traditional WU approach for both the sprint and distance events, performing less high-intensity and more moderate-intensity exercise during their WUs than planned. In addition, elements likely relevant to successful performance in cross-country skiing were missing from WU plans.

Gardening Tasks Performed by Adults are Moderate- to High-Intensity Physical Activities

The objective of this study was to determine the exercise intensities of 10 gardening tasks for men and women in their 20s. Fifteen university students [(mean ± SD) age 24.7 ± 1.4 years and body mass index 23.5 ± 4.1 kg·m−2] participated in this study. On two occasions, the subjects completed 10 gardening tasks in a high tunnel and a grassy area with weeds located near the high tunnel in Cheongju, Chungbuk, South Korea. They performed five gardening tasks randomly ordered on each occasion. Subjects did each gardening task for 5 minutes and then sat and rested in a chair for 5 minutes before the next task. Each subject wore a portable telemetric calorimeter and respired into the facemask during the gardening tasks and resting periods to measure their oxygen uptake. The subjects also wore a heart rate monitor under their breast to record heart rate data during the gardening tasks and resting periods via radiotelemetry. The 10 gardening tasks performed by the subjects were determined to be moderate- to high-intensity physical activities [3.5 ± 0.5 to 6.3 ± 1.2 metabolic equivalents (MET)]. In conclusion, the exercise intensity of gardening tasks should be useful information for developing garden exercise programs that meet the recommended physical activity for health benefits in adults.

Fitness Load and Exercise Time in Secondary Physical Education Classes

This study investigated the effect of secondary school physical education on fitness load. Fitness load was defined as the product of the mean heart rate above threshold (144 bpm) and fitness time (the duration of the heart rate above threshold). The relationship of fitness load and skill level of students was also studied. Teachers of 24 classes classified students as having high, moderate, or low skill ability. Seventy-two students, 1 from each skill level in each class, wore heartwatches to record heart rate at 15-s intervals. Student behavior was videotaped and coded. Twenty-one percent of the classes produced an overload effect, and 79% did not. The highly and moderately skilled students achieved fitness load more frequently than their lower skilled colleagues. The relationship between fitness load and percentage of time exercising was r = .66, indicating 44% common variance.