Walking faster, not just walking, helped frail older adults climb out of frailty

Walking is the exercise older people choose most often. A trial from Northwestern University asked a simple question: does the pace matter for people who are already frail? In 16 weeks, those who walked briskly were more likely to become less frail than those who strolled. The trial was randomized and blinded, but more than a third of the people who signed up did not finish, and the result is less certain once that is taken into account.

Frailty is a state in which several things go wrong at once: weight loss, exhaustion, weakness, slow walking and little activity. People with one or two of these signs count as "prefrail", with three or more as frail. Frailty raises the risk of hospital stays and death. Exercise is known to slow its progress, but the authors note that clear evidence that exercise can reverse existing frailty, and guidance on how hard people should exercise, have been missing.

What they did

The team enrolled 14 independent-living retirement communities in and around Chicago, ranging from modest to expensive. Whole communities, not single people, were randomly assigned to one of two walking programs. This "cluster" design kept residents from seeing that another group walked at a different speed. Participants were told only that they were in a walking study, and the people measuring the results did not know who was in which group.

In total, 165 people over 60 who were prefrail or frail enrolled. Everyone had one-on-one, supervised 45-minute walking sessions three times a week for 16 weeks, in the hallways and stairwells of their own building:

• Brisk walking: walk fast, aiming for more than 70% of the estimated maximum heart rate, or a feeling of hard effort.
• Casual walking: a relaxed, comfortable pace, well below that.

The only difference between the groups was speed. The main measure was whether a person moved down at least one frailty category (from frail to prefrail, or prefrail to not frail) on a standard questionnaire that also includes a grip-strength test.

What they found

Of the 165 who enrolled, 105 completed the program and were analyzed (average age 79, 79% women, about two-thirds using a cane or walker).

• Frailty: 70% of brisk walkers (32 of 46) moved to a less frail category, against 46% of casual walkers (26 of 56). The brisk walkers had about three times the odds of improving.
• Walking ability: brisk walkers gained more in everyday walking speed (0.08 metres per second more) and covered about 49 metres more in a six-minute walking test.
• Daily activity: measured with a thigh-worn sensor, brisk walkers took 985 more steps per day than casual walkers after the program.
• Effort and attendance: the brisk group really did work harder (71% versus 59% of maximum heart rate), and both groups completed a similar number of sessions (a median of 35 and 36 of 48).
• No difference was found on the other measures, including balance, a combined test of balance, walking and standing up from a chair, and the continuous frailty score.

Safety was reassuring: across 3,354 sessions, about 0.3% were linked to an adverse event. The one event clearly caused by the program was a fall without injury in the brisk group. The 13 serious adverse events during the trial (9 in the casual group, 4 in the brisk group) were judged unrelated to walking.

What to keep in mind

• Many dropped out. About 36% of enrolled participants were not in the final analysis because they withdrew, were lost to follow-up or died. When the team re-ran the analysis under assumptions about the missing people, the advantage of brisk walking became smaller and was no longer statistically significant. The authors say the size of the effect still looked clinically meaningful.
• Who took part. Most were white women living in retirement communities, so the results may not apply to everyone. The program was supervised one-on-one, and the team says it is unknown whether unsupervised or group walking would work as well.
• No untreated group. Both groups walked, on purpose, so the trial shows that faster beats slower, not how either compares with doing nothing.
• Short term. The study ended at 16 weeks and did not follow people afterwards.

Why it matters

Many older people already walk, and the instruction tested here was simple: walk as fast as you safely can. In this trial, frail older adults could keep up that pace about as reliably as a gentle one, and it moved more of them out of a frailty category and into more daily activity. The authors suggest that intensity may be a key setting when exercise programs for frail people are designed. Because so many participants did not finish, a larger trial that keeps more people on board would make the case firmer.