It is said that old age brings wisdom and that may be true for some individuals, but at the same time, for some getting on in years also brings diminishment in exercise and cognitive capacity. Not everyone will be affected equally; physically active individuals with good genetics maintaining a healthy diet perform better than their inactive counterparts eating junk food and smoking. However, from the standpoint of healthcare systems, what really matters is the average health and well-being of an entire demographic group and the utilisation of convenient and cost-effective diagnostic methods.
In this blog you will learn:
The 6MWT was originally designed for evaluating exercise tolerance/functional capacity in patients with cardiopulmonary issues (e.g. chronic respiratory diseases and heart failure), but quickly found use in individuals with non-cardiopulmonary issues . Those include complex neuromuscular diseases like Charcot-Marie-Tooth disease, spinal muscular atrophy, and conditions such as fibromyalgia and multiple sclerosis (MS) [2, 3, 4, 5].
More disease-specific and advanced diagnostic tools and methods aside, the 6MWT is a convenient, cost-effective, and clinically proven method for identifying any reductions in functional capacity or improvement of therapeutic intervention(s). This non-specific yet comprehensive nature of the 6MWT has its drawbacks and advantages—depending on what purpose the test is utilised for.
Evaluating exercise capacity in seniors, a vast demographic with age as the only common denominator, for the purpose of recognising individuals in need of special instructions for exercising and identifying those who are unable to exercise at all in a timely manner is one such example. The non-specific comprehensive evaluation of cardiopulmonary and muscular fitness, represented as distance walked in six minutes, is therefore a significant advantageous feature of the 6MWT. But what are representative walking distances in seniors, in those otherwise healthy, and those afflicted with various diseases?
It should come as no surprise that average walking distances obtained with the 6MWT in young, healthy adults significantly differ from those in patients with even mildly severe cardiopulmonary or (neuro)muscular diseases and even more in the elderly. A comprehensive study encompassing participants from seven countries found that the average distance was 611 ± 85 m in the 40–49 age group and fell all the way down to 514 ± 71 m for the group of 70–80-year-olds . Diseases shorten that distance even further.
For example, one study of the 6MWT in patients with chronic obstructive pulmonary disease (COPD) found that those with particularly severe form and cardiovascular issues had walked only 256 ± 73 m . In contrast, a comparable group of healthy individuals had walked on average 559 ± 80 m or more than twice the distance . However, it should be kept in mind that 6MWT score/distance is also influenced by the patient’s gender, height, and body mass index (BMI) .
Regarding accurate average 6MWT distances in healthy seniors, a comprehensive meta-analysis of 13 separate studies found that the average walking distance (for men) was 560 m in the 60–69 age group, 530 m amongst 70–79-year-olds and 446 m in the 80–89 group . Disparity between genders was most prominent in the oldest age group (80–89 years), females walked a mere 382 m (or 64 m less than males of the same age) . Differences are, of course, even more pronounced between healthy senior individuals and patients with other accompanying diseases.
There are few dedicated studies touching upon the effects of diseases and conditions on the 6MWT in seniors. One study investigated obesity and found significant inverse correlation between walking distance and speed and positive correlation with severity of dyspnoea and musculoskeletal pain . Another looked at impact of impaired muscle strength on the 6MWT walking distance . Yet others examined the effects of conditions of cardiopulmonary nature which, not surprisingly, had the most significant impact . In connection with the latter, we should highlight another useful application of the 6MWT—identifying individuals who would particularly benefit from the most well-known conservative treatment method.
The benefits of guided physical exercise in seniors are numerous and well-documented. Loss of muscle mass and strength and losses in bone density, a staple of the ageing process, can be mitigated or even reversed (to a certain extent) with regular exercise [13-16]. The same can be said for CVDs: regular exercise is associated with a lowered risk of coronary artery disease (CAD) and stroke (particularly ischaemic stroke) [17, 18, 19]. Lastly, exercise is beneficial as a preventive measure against dementia and for delaying further cognitive decline in those already experiencing such issues [20, 21].
However, seniors differ greatly in their exercise capacity and some have conditions that preclude or limit certain types of exercise. There are various methods of identifying those individuals, but few as convenient as the 6MWT—as demonstrated by the comprehensive study encompassing 156 community-dwelling elderly individuals . Researchers investigated the association between 6MWT distances and health status and found significant correlation: poorer health status translated to shorter distance walked . Additionally, the 6MWT proved useful in stratifying tested individuals into groups in accordance with their functional fitness . Said categorisation can then be used for preparing exercise guidelines for those less able or those with specific disabilities .
The 6MWT is a versatile and comprehensive tool for assessing exercise capacity in seniors and as such suitable for identifying those individuals who would benefit from special instructions for exercise or would need a guided exercise regime.
Interested in finding out more about the use of the 6MWT in the management of other conditions? Read about assessing heart failure, assessing pulmonary arterial hypertension and assessing respiratory function.