Acute breathing patterns in healthy and heart disease participants during cycling at different levels of immersion

Respiratory function and breathing response to water- and land-based cycling at the matched oxygen uptake

The impact of underwater exercise on respiratory function remains unclear when its metabolic rate is matched with exercise performed on land. Therefore, we compared the breathing responses and respiratory function during and after water (WC)- and land (LC)-based cycling performed at the matched oxygen uptake (VO2 ). Twelve healthy men performed 15 min of incremental WC and LC on separate days. During WC, participants cycled continuously at 30, 45, and 60 rpm (stages 1, 2, and 3) for 5 min each. During LC, participants cycled at 60 rpm for 15 min while wattage was increased every 5 min and adjusted to match VO2 to the WC condition. Breathing patterns during cycling and spirometry data before and after cycling were collected. VO2 during WC and LC was similar. Respiratory rate (WC: 27 ± 3 vs. LC: 23 ± 4 bpm, p = 0.012) and inspiratory flow (WC: 1233 ± 173 vs. LC: 1133 ± 200 ml/s, p = 0.035) were higher and inspiratory time (WC: 1.0 ± 0.1 vs. LC: 1.2 ± 0.2 s, p = 0.025) was shorter at stage 3 during WC than LC. After WC, forced vital capacity (p = 0.010) significantly decreased while no change was observed after LC. These results suggest that at similar metabolic rates during WC and LC, breathing is slightly shallower during WC which may have chronic effects on respiratory muscle function after multiple bouts of aquatic cycling. Underwater exercise may be beneficial for respiratory muscle rehabilitation when performed on a chronic basis.

Aquatic cycling-What do we know? A scoping review on head-out aquatic cycling

Over the past few years, aquatic cycling has become a trending fitness activity. However, the literature has not been reviewed exhaustively. Therefore, using scoping review methodology, the aim of this review was to explore the current state of the literature concerning aquatic cycling. This study specifically focused on study designs, populations and outcomes. A comprehensive search of seven databases (PubMed, MEDLINE, Cinahl, Embase, PEDro,Web of Science, WorldCat) was conducted up to 30^th September 2016. GoogleScholar, World Cat, ResearchGate, specific aquatic therapy websites and aquatic therapy journals were searched to identify additional literature. Full-text publications in English, German or Dutch were included. Studies were included when the intervention involved head-out cycling carried out in 10° to 35° Celsius water. Exclusion criteria were the use of wet suits or confounding interventions that would affect participants’ homeostasis. 63 articles were included and the study parameters of these studies were summarized. Using three grouping themes, included studies were categorised as 1) single session tests comparing aquatic versus land cycling, or 2) aquatic cycling only sessions investigating different exercise conditions and 3) aquatic cycling intervention programmes. Although the experimental conditions differed noticeably across the studies, shared characteristics were identified. Cardiovascular parameters were investigated by many of the studies with the results suggesting that the cardiac demand of aquatic cycling seems similar to land-based cycling. Only six studies evaluated the effect of aquatic cycling interventions. Therefore, future research should investigate the effects of aquatic cycling interventions, preferably in individuals that are expected to gain health benefits from aquatic cycling. Moreover, this comprehensive outline of available literature could serve as a starting point for systematic reviews or clinical studies on the effects of aquatic cycling on the cardiovascular responses.