Short-term entrainment of ventilation to the walking cycle in humans

Abstract

We describe a breath-by-breath method to test for entrainment of breathing and walking cycles. Thirty-eight normal subjects walked comfortably on a treadmill while breathing through a pneumotachograph. We analyzed the time intervals between heel strikes and the onset of inspiration (or expiration) for evidence of phase locking between steps and breaths, using Monte Carlo simulation to model the probability that n consecutive inspirations (or expirations) would begin at a constant time interval +/- 0.10 s from heel strikes by chance. We developed empirical criteria for rhythm synchronization during series of four or more breaths, while maintaining an estimated specificity of 95%. The majority of subjects showed some evidence of entrainment (29 +/- 23% of breaths on average), which occurred intermittently, usually lasting less than 10 breaths at a time. The precision of phase locking during spontaneous entrainment was similar to that in 10 subjects who attempted to maintain deliberate entrainment. The results suggest that the walking cadence provides a persuasive, but not dominant, input to the central breathing pattern generator. The present method can detect entrainment even when it occurs sporadically or with varying coupling pattern.

Analysis of co‐ordination between breathing and exercise rhythms in man.

“…Although the majority of authors searching for a kind of co-ordination or coupling between exercise rhythm and rhythm of breathing found some relationship (e.g. Bechbache & Duffin, 1977; Jasinskas, Wilson & Hoare, 1980;Bramble & Carrier, 1983;Paterson, Wood, Morton & Henstridge, 1986;Paterson, Wood, Marshall, Morton & Harrison, 1987;Hill, Adams, Parker & Rochester, 1988), there are also reports that breathing and exercise rhythms are independent (Kelman & Watson, 1973;Kay, Petersen & Vejby-Christensen, 1975). The variety of the results may be explained by differences in experimental design, in the type of exercise and other experimental conditions and methods of evaluation which in turn make a quantitative comparison between the different studies more difficult.…”

Lungs And Legs: Entrainment Of Breathing To Locomotion In Highly Trained Distance Runners

“…Research on humans while running has shown that entraining breathing frequency to stride rate improves running economy (Bernasconi & Kohl, 1993;Bonsignore et al, 1998;Bramble & Carrier, 1983), possibly by improving the economy of ventilation by reducing the metabolic cost of breathing (Bramble & Carrier, 1983;Heinrich, 2001;Hill et al, 1988;Paterson et al, 1986).…”

“…Entrainment has also been shown to occur, sometimes infrequently or transiently, in humans while walking and running (Bechbache & Duffin, 1977;Bernasconi & Kohl, 1993;Berry et al, 1988;Bonsignore et al, 1998;Bramble & Carrier, 1983;Hill et al, 1988;McDermott et al, 2003;Paterson et al, 1987;Raßler & Kohl, 1996;Takano, 1995), cycling (Bechbache & Duffin, 1977;Bernasconi & Kohl, 1993;Bonsignore et al, 1998;Jasinskas et al, 1980;Paterson et al, 1986), rowing (Mahler et al, 1991), and even while walking with crutches (Hurst et al, 2001) ( Table 1). Animals that run on four legs seem to be constrained to a 1:1 ratio between steps and breaths, especially as speed increases (Boggs, 2002;Lafortuna et al, 1996;Simons, 1999 (Bramble & Carrier, 1983).…”

“…There is considerable evidence that a pattern exists between breathing and stride rate in animals (Baudinette et al, 1987;Brackenbury & Avery, 1980;Bramble & Carrier, 1983;Iscoe, 1981;Kamau, 1990) and humans (Bechbache & Duffin, 1977;Bramble & Carrier, 1983;Berry et al, 1988;Bonsignore et al, 1998;Hill et al, 1988;McDermott et al, 2003;Paterson et al, 1987;Raßler & Kohl, 1996;Takano, 1995), although this pattern does not seem to be preset, as many of the studies on humans have shown it to be infrequent or dependent on other factors, such as fitness level.…”

“…A number of researchers have suggested that entraining breathing to stride rate may reduce the metabolic cost of ventilation (Bramble & Carrier, 1983;Heinrich, 2001;Hill et al, 1988;Paterson et al, 1986). Therefore, it is possible that the economy of running, one of the most overlooked parameters of aerobic function, is improved by creating a synergy between two vastly different mechanisms-breathing and locomotion-by coordinating the activity of one's lungs to that of one's legs.…”