Differences in the prefrontal cortex responses of healthy young men performing either water-based or land-based exercise at light to moderate intensity

• Published in: Experimental brain research Vol. 241; no. 4; pp. 991 - 1000
• Main Authors: Hashitomi, Tatsuya, Hoshi, Daisuke, Fukuie, Marina, Tarumi, Takashi, Sugawara, Jun, Watanabe, Koichi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2023; Springer; Springer Nature B.V
• Subjects: Adult; Biomedical and Life Sciences; Biomedicine; Blood flow; Blood pressure; Carbon dioxide; Cerebral blood flow; Exercise; Exercise - physiology; Exercise intensity; Health aspects; Heart beat; Heart Rate; Hemoglobin; Humans; Immersion; Male; Measurement; Medical examination; Neurology; Neurosciences; Oxyhemoglobins - analysis; Oxyhemoglobins - metabolism; Physical training; Prefrontal cortex; Prefrontal Cortex - physiology; Research Article; Respiration; Water; Young Adult; Young men; Japan; Water cycling; Prefrontal cortex; Functional near-infrared spectroscopy; Water immersion; Oxy-Hb
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-023-06583-z

Cerebral blood flow increases more during water-based exercise than land-based exercise owing to the effects of end-tidal CO
2
(PETCO
2
) and mean arterial pressure (MAP) changes due to water immersion. However, it is unclear whether oxygenated hemoglobin (oxy-Hb) concentrations in the prefrontal cortex (PFC) are increased more by water-based or land-based exercise. We hypothesized that oxy-Hb concentrations in the PFC are higher during water-based exercise than land-based exercise when the exercise intensity is matched. To test this hypothesis, 10 healthy participants (age: 24.2 ± 1.7 years; height: 1.75 ± 0.04 m; weight: 69.5 ± 5.2 kg) performed light- to moderate-intensity cycling exercise in water (water-based cycling (WC); chest-high water at 30 °C) and on land (LC). Stroke volume, cardio output, heart rate, MAP, respiratory rate, PETCO
2
, and oxy-Hb in the PFC were assessed during 15 min of exercise, with exercise intensity increased every 5 min. Both WC and LC significantly increased oxy-Hb concentrations in the PFC as exercise intensity was increased (intensity effect:
p
 < 0.001). There was no significant difference in oxy-Hb concentrations during WC and LC in most prefrontal areas, although significant differences were found in areas corresponding to the left dorsolateral PFC (exercise effect:
p
 < 0.001). Thus, WC and LC increase oxy-Hb concentrations in the PFC in a similar manner with increasing exercise intensity, but part of the PFC exhibits enhanced oxy-Hb levels during WC. The neural response of the PFC may differ during water-based and land-based exercise owing to differences in external information associated with water immersion.