Sex Differences in Heart Rate Response to Isometric Handgrip Exercise with Concurrent Contralateral Forearm Somatosensory Stimulation
Bibliographic record
Abstract
Background Pharmacological evidence indicates that baseline cardiovagal mechanisms determine the rapid heart rate (HR) response to the onset of moderate intensity isometric handgrip (IHG) exercise. The HR response at exercise onset expresses sex differences, being less in females. Further, somatosensory nerve stimulation (STIM) appears to affect baseline cardiovagal control in some supine participants. Objective This study explored the effect of STIM on HR and heart rate variability (HRV) during short‐duration moderate‐intensity IHG in supine healthy adults and explored whether this effect expresses sex differences. Participants Twenty‐four young healthy individuals aged 23 ± 1.9 years (18 females (F): 165 ± 7.4cm, 63 ± 13kg, BMI 23 ± 2kg/m 2 ; 6 males (M): 179 ± 2.2cm, 79 ± 11kg, BMI 25 ± 3.3kg/m 2 ). Methods Participants performed six isometric handgrips with their right hand at 30 to 40% of their maximal grip strength, each lasting 20 to 30 seconds and separated by one minute of rest. Three of these IHG contractions were performed during simultaneous administration of sub‐motor STIM provided by transcutaneous electrical nerve stimulation (TENS; 100 Hz, 50 μs) on the medial contralateral forearm through anesthetized skin for the duration of the handgrip. A 3‐lead ECG provided R‐R interval data. Systolic (SBP) and diastolic blood pressure (DBP) were monitored, as well as, heart rate (HR), root mean square of successive differences in R‐R intervals (RMSSD) as a measure of HRV, and respiration. Data were analysed using two‐factor ANOVA with Bonferroni correction, and independent t‐tests. Results The ΔHR from baseline to IHG without STIM was greater in males compared to females (12 ± 6bpm versus 6 ± 6bpm, respectively; d = 1.00). No differences in ΔHR were detected for either sex when STIM was added to the IHG. Of the 18 F participants, 4 provided a minimal HR response (ΔHR > 4bpm) to the IHG without STIM (F1: 77 to 79bpm; F2: 69 to 70 bpm; F3: 50 to 50bpm; F4: 62 to 62 bpm) which resolved in 3 of the 4 F participants with application of STIM (F1:73 to 83bpm; F3: 45 to 59bpm; F4: 54 to 60bpm). Further, no statistically significant differences were observed in ΔRMSSD from baseline to IHG without STIM (p = 0.0321; M: 77 ± 68ms to 30 ± 145ms; F: 74 ± 38ms to 54 ± 39ms) and with STIM (p = 0.953; M: −28 ± 61ms and F: −30 ± 21ms). Conclusion Our preliminary findings suggest that, in supine individuals, sex differences exist in the HR response at the exercise onset but these effects are not modified by concurrent sub‐motor somatosensory nerve stimulation. Support or Funding Information Supported by Natural Science and Engineering Research Council of Canada This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".