Fourteen sedentary 50- to 55-year-old men were exercised to exhaustion using an incremental treadmill protocol. Mean (±SEM) peak oxygen uptake (V̇O2peak) was 40.5 ± 1.19 ml · kg1 · min−1, and maximum heart rate was 161 ± 4 beats · min−1. Blood lactate concentration was measured regularly to identify the lactate threshold (oxygen consumption at which blood lactate concentration begins to systematically increase). Threshold occurred at 84 ± 2% of V̇O2peak. The absolute lactate value at threshold was 2.9 ± 0.2 mmol · L−1. On a separate occasion, 6 subjects exercised continuously just below their individual lactate thresholds for 25 min without significantly raising their blood lactate levels from the 10th minute to the 25th. The absolute blood lactate level over the last 20 min of the steady-state test averaged 3.7 ± 1.2 mmol · L−1. This value is higher than that elicited at the threshold in the incremental test because of the differing nature of the protocols. It was concluded that although the lactate threshold occurs at a high percentage of V̇O2peak, subjects are still able to sustain exercise at that intensity for 25 min.
Fiona Iredale, Frank Bell and Myra Nimmo
K. Fiona Iredale and Myra A. Nimmo
Thirty-three men (age 26–55 years) who did not exercise regularly were exercised to exhaustion using an incremental treadmill protocol. Blood lactate concentration was measured to identify lactate threshold (LT, oxygen consumption at which blood lactate concentration begins to systematically increase). The correlation coefficient for LT (ml · kg−1 · min−1) with age was not significant, but when LT was expressed as a percentage of peak oxygen consumption (VO2 peak), the correlation was r = +.69 (p < .01). This was despite a lack of significant correlation between age and VO2 peak (r = −.33). The correlation between reserve capacity (the difference between VO2 peak and LT) and age was r = −.73 (p < .01 ), and reserve capacity decreased at a rate of 3.1 ml · kg−1 · min−1 per decade. It was concluded that the percentage of VO2 peak at which LT occurs increases progressively with age, with a resultant decrease in reserve capacity.
Annette J. Raynor, Fiona Iredale, Robert Crowther, Jane White and Julie Dare
Regular physical activity has multiple benefits for older adults, including improved physical, cognitive, and psychosocial health. This exploratory study investigated the benefits of a 12-week exercise program for older adults (n = 11 control and n = 13 intervention) living in a residential aged care facility in Perth, Western Australia. The program, prescribed and delivered by an accredited exercise physiologist, aimed to maintain or improve participants’ physical capacity. It comprised one-on-one exercise sessions (1 hr × 2 days/week × 12 weeks), involving a components-approach intervention. Physical performance measures (balance, strength, flexibility, and mobility) were assessed preintervention and postintervention. Qualitative interviews postintervention with residents participating in the exercise intervention, and with family members, staff, and research team members, explored barriers and enablers to participation and perceived psychosocial outcomes. Findings indicate the program provided physical benefits and enhanced social engagement for participants, illustrating the value of providing exercise physiology services in the aged care sector.