Hypotheses from the vertebrate literature explaining lowered ventilation rate and heart rate after sudden stimuli
| Hypothesis . | Reference . |
|---|---|
| (1) Decreased heart rate, decreased ventilation rate and behavioural freezing reduce movement and noise from the animal. This helps it hide from predators. | Jacobsen, 1979; Barham et al., 1985 |
| (2) Ventilation rate and heart rate slow because metabolic rate drops. Lowered metabolic rates allow diving and burrowing air-breathing vertebrates to remain hidden underwater or in a hypoxic den for longer. | Smith and Woodruff, 1980; Smith et al., 1981 |
| (3) In preparation for flight, blood is redistributed from vegetative to locomotory muscles. This causes a reflexive drop in heart rate. | Laming and Savage, 1980; Laming and Austin, 1981 |
| (4) Heart rate drops to reduce blood pressure. This protects delicate tissues and capillaries during the subsequent increase in blood pressure at the onset of locomotion. | Ide and Hoffmann, 2002; Cooke et al., 2003 |
| Hypothesis . | Reference . |
|---|---|
| (1) Decreased heart rate, decreased ventilation rate and behavioural freezing reduce movement and noise from the animal. This helps it hide from predators. | Jacobsen, 1979; Barham et al., 1985 |
| (2) Ventilation rate and heart rate slow because metabolic rate drops. Lowered metabolic rates allow diving and burrowing air-breathing vertebrates to remain hidden underwater or in a hypoxic den for longer. | Smith and Woodruff, 1980; Smith et al., 1981 |
| (3) In preparation for flight, blood is redistributed from vegetative to locomotory muscles. This causes a reflexive drop in heart rate. | Laming and Savage, 1980; Laming and Austin, 1981 |
| (4) Heart rate drops to reduce blood pressure. This protects delicate tissues and capillaries during the subsequent increase in blood pressure at the onset of locomotion. | Ide and Hoffmann, 2002; Cooke et al., 2003 |