Metabolic costs and heart rate responses to treadmill walking in water at different depths and temperatures

Abstract

Treadmill walking/jogging in water is a potentially useful therapeutic modality. Since energy costs of this activity are unknown, we compared oxygen consumption (VO2) of treadmill walking/jogging in water to a dry treadmill at speeds of 40.23 to 160.9 meters/min (m/m) in 13.4 m/m increments in 11 subjects. At speeds greater than or equal to 53.6 m/m, ankle depth, below knee, midthigh, and waist depth walking/jogging in water significantly elevated VO2 and heart rate (HR) above dry treadmill walking (P less than 0.05). At speeds greater than or equal to 134.1 m/m, VO2 of waist depth jogging was not significantly greater than dry jogging. These findings showed no gender specificity. Treadmill walking/jogging in waist depth water at temperatures of 30.5 degrees C and 36.1 degrees C was compared to dry treadmill walking in five subjects. The rate of increase of HR compared to VO2 was significantly greater at 30.5 degrees C than dry walking, and greater at 36.1 degrees C than 30.5 degrees C (P less than 0.05). Treadmill walking in water can double the oxygen cost of movement depending on the depth and speed, and the response to increasing speed is nonlinear. Water temperature affects the relationship of HR to VO2 at waist depth, suggesting that water temperature can add a significant thermal load to the cardiovascular system. Metabolic and cardiovascular demands of treadmill walking/jogging in water must be considered when using this modality since greater external work results at much lower speeds than on land.

Underwater Treadmill Exercise as a Potential Treatment for Adults With Osteoarthritis

“…This contention is supported by previous research, which indicated that walking at speeds less than 0.97 m/s, buoyancy dominates and less energy is expended in water than land because fluid resistance is relatively low due to low limb velocities (Hall et al, 2004). When speeds are greater than 0.97 m/s, limb velocities increase and fluid resistance may offset buoyancy and lead to similar energy expenditures during water and land treadmill exercise (Gleim & Nicholas, 1989;Hall et al, 2004;Hall et al, 1998;Rutledge et al, 2007). The results of the current study support this observation.…”

“…We would postulate that some of the mixed results reported in the literature (Hinman et al, 2007;Lund et al, 2008;Wang et al, 2007) may in part be related to this lack of control over exercise intensity. This contention is supported by Gleim and Nicholas (1989), who observed that different water levels contribute to different energy expenditures in healthy adults. Currently, the effectiveness of using an underwater treadmill as a therapy protocol in patients with OA has not been tested One of the challenges with prescribing underwater treadmill exercise in OA patients is determining a gait speed that may lead to therapeutic gains.…”

“…The authors are with the Utah State University Heath, PE, and Recreation Department in Logan, UT. of energy (Gleim & Nicholas, 1989;Hall, Macdonald, Maddison, & O'Hare, 1998) while still reducing stress and impact forces on the lower extremity joints (Barela & Duarte, 2008;Barela, Stolf, & Duarte, 2006).…”

Maximal Physiological Responses to Deep Water Running at Thermoneutral Temperature.

“…Increased stroke volume allows for the maintenance of cardiac output with lower HR (Christie et al, 1990). A reflex response of the cardiovascular system to the cold receptors in the skin could also have contributed to the depressed HR in the water as the water temperature of 32.5 C is slightly lower than thermoneutral for the resting condition (McArdle et al, 1976;Gleim et al, 1989).…”

“…When exercising above thermoneutral water temperature, HR increases more rapidly because a greater cardiac output is directed to the skin (Nadel, 1984). Imposing the additional heat load due to exercise in this environment is likely to cause a significant effect on the circulation (Gleim and Nicholas, 1989). To our knowledge, almost all previous studies (Frangolias and Rhodes, 1995;Svedenhag and Seger, 1992;Town and Bradley, 1991;Butts et al, 1991ab) which compared maximal physiological responses to DWR with treadmill running (TMR) has been conducted below the thermoneutral water temperature.…”