Publications by authors named "Harrison Wittels"

Executing flight operations demand that military personnel continuously perform tasks that utilize low- and high-order cognitive functions. The autonomic nervous system (ANS) is crucial for regulating the supply of oxygen (O2) to the brain, but it is unclear how sustained cognitive loads of different complexities may affect this regulation. Therefore, in the current study, ANS responses to low and high cognitive loads in hypoxic and normoxic conditions were evaluated.

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Sport coaches increasingly rely on external load metrics for designing effective training programs. However, their accuracy in estimating internal load is inconsistent, and their ability to predict autonomic nervous system (ANS) deterioration is unknown. This study aimed to evaluate the relationships between internal and external training load metrics and ANS recovery and function in college football players.

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Reduced heart rate variability (HRV) is an autonomic nervous system (ANS) response that may indicate dysfunction in the human body. Consistent evidence shows cancer patients elicit lower HRV; however, only select cancer locations were previously evaluated. Thus, the aim of the current study was to explore HRV patterns in patients diagnosed with and in varying stages of the most prevalent cancers.

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Article Synopsis
  • Exercise in higher core temperatures can negatively impact the autonomic nervous system (ANS) function, particularly with longer training durations.
  • The study tracked 50 Division I collegiate football players to analyze correlations between training duration and ANS recovery at core temperatures of ≥37 °C, ≥38 °C, and ≥39 °C.
  • Significant negative associations were found between training duration and ANS metrics like heart rate recovery and heart rate variability (HRV) as core temperatures increased, indicating that hotter conditions worsen ANS recovery.
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Background: Evidence shows relaxation techniques reactivate the parasympathetic nervous system (PNS) following physiological stressors such as exercise. As such, these techniques may be useful following exercise training of high intensity sports, like collegiate football.

Purpose: To evaluate the impact of mindfulness and rest activities on PNS reactivation following training sessions, in a sample of Division-I collegiate, male football athletes.

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Military aviators endure high cognitive loads and hypoxic environments during flight operations, impacting the autonomic nervous system (ANS). The synergistic effects of these exposures on the ANS, however, are less clear. This study investigated the simultaneous effects of mild hypoxia and high cognitive load on the ANS in military personnel.

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Current metrics like baseline heart rate (HR) and HR recovery fail in predicting overtraining (OT), a syndrome manifesting from a deteriorating autonomic nervous system (ANS). Preventing OT requires tracking the influence of internal physiological loads induced by exercise training programs on the ANS. Therefore, this study evaluated the predictability of a novel, exercise cardiac load metric on the deterioration of the ANS.

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Article Synopsis
  • The autonomic nervous system (ANS) is crucial for athletes' performance, and insufficient recovery during training can hurt their performance.
  • A study tracked collegiate football players over 13 weeks, using armband monitors to assess their exercise cardiac load (ECL), heart rate (HR), and heart rate variability (HRV) to gauge ANS function and recovery.
  • Findings revealed that higher ECLs negatively impacted running speed, while better HRV was linked to improved speed, suggesting that managing training intensity and recovery is essential for optimal performance during the season.
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The autonomic nervous system (ANS) is profoundly affected by high intensity exercise. However, evidence is less clear on ANS recovery and function following prolonged bouts of high intensity exercise, especially in non-endurance athletes. Therefore, this study aimed to investigate the relationships between duration and intensity of acute exercise training sessions and ANS recovery and function in Division I football athletes.

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Introduction: Photoplethysmography (PPG) is the science behind many commonly used medical devices such as the pulse oximeter. PPG changes, herein as "PPG dropouts," have been described in existing in vitro studies following artificially induced clot activation. Because COVID-19 causes increased arterial, venous, and microvascular clot formation, our hypothesis is that PPG dropouts identified in vitro can also be found in vivo in patients with COVID-19.

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Introduction: The Tiger Tech Warfighter Monitor (WFM) is a novel single-limb device for ECG acquisition. The WFM provides true (not derived) single limb Electrocardiogram monitoring (ECG) to provide heart rate and R-R interval monitoring between QRS complexes. Herein, we evaluate the diagnostic accuracy of the WFM heart rate, R-R interval monitoring, and heart rate variability monitoring in comparison to a 2‑lead chest ECG.

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