A partnership between Australian Fitness Network, the University of the Sunshine Coast and the Australian Institute of Fitness, Fitness Research studies the populations, communities and environments related to the fitness industry, with the mission of improving the health of Australians through an improved body of fitness knowledge.
Introduction: The current guidelines for fitness and cardiovascular training have not been well researched in
at-risk populations such as the aged or elderly. Typically, training guidelines for the aged are modified from other populations, and specific research into the response from different training protocols for the elderly has only recently been published.
The purpose of this study was to examine the physiological responses in the elderly using cycle ergometers across two different protocols, constant and interval.
Methods: Sixteen subjects with an average age of nearly 70 years participated in the study. All participants were generally active, doing roughly 90 minutes of activity each week and initial VO2 predicted results were approximately 34 mL-kg-1-min. Participants were tested on two separate mornings, having fasted overnight. Testing included ECG and expired gas analysis while pedalling an electronically braked cycle ergometer. The session was divided into five different phases: resting baseline; warm up; exercise; cool down; and post-exercise resting. For the constant session the exercise phase involved 20 minutes of pedalling at 50 per cent of extrapolated VO2 max. For the interval session the exercise phase involved 20 minutes of alternating intensity equal to 70 per cent VO2 max for 1 minute followed by 1 minute of 30 per cent VO2 max. The subjects were asked to indicate their RPE using the 6 to 20 Borg scale after each minute of exercise in the exercise phase.
Research paper: Response to Constant and Interval Exercise Protocols in the Elderly
Results: There was no statistically significant difference between the two different types of activity. Total number of litres of oxygen used between the two different protocols was 28L for constant and 29L for interval. While the heart rates (HR) varied – as may be expected – during the interval section, as the graph below illustrates, the two different HR graphs almost matched each other for change over the 20-minute period. There was less than 1.2 per cent relative difference between the two HR values. RPE values were also nearly identical, with an average RPE of 11.4 for the constant session and 11.3 for the interval session.
Note: It should be pointed out that the constant protocol was only at 50 per cent, and the interval was only at 70 per cent and 30 per cent. This means the constant was not in the usual effort range recommend for improved fitness. Further, the high level for interval was also below that normally used for higher intensity interval training. As this was one of the first research projects using elderly study subjects, it was important to establish a baseline for response, and as such the intensities used allowed this to occur. Future research into the elderly may take these levels higher, but this is not without risk. The elderly are already considered to be an at-risk population, and for higher intensities to be used, there will be additional ethical considerations required, such as having medical staff on hand during testing.
"Oxygen consumption was 16 per cent higher for the interval session, suggesting that if you are working with an older client, using an interval protocol may help boost cardiovascular fitness faster than simply maintaining a constant intensity."
Take home message: The participants in this study all exhibited a similar response between the two different types of training. Further, there was no real difference between the responses when comparing older males and older females. Oxygen consumption was 16 per cent higher for the interval session, suggesting that if you are working with an older client, using an interval protocol may help boost cardiovascular fitness faster than simply maintaining a constant intensity. This has yet to be proved, but there is much evidence from previous interval-related research showing that interval training provides a quicker improvement in fitness if the individual already has a general fitness base. An additional notable finding from this research was participant feedback showing the interval training protocol to be much more popular than the constant training. Study subjects agreed that if they were to do a regular cycling workout they would prefer to use the interval protocol ahead of the constant.
Summary: Interval training as shown in this study appears to be a safe and effective method of increasing heart rate and oxygen output when compared with constant intensity training in the elderly.