# Twenty-one older adults made 111 percent more listening errors on land than in chest-deep water, while immersion also doubled one balance-complexity measure and pushed sway area and velocity in the same direction, showing how a pool can lighten vigilance demands even as upright control becomes more challenging

> Twenty-one healthy older adults in their early seventies showed a striking split between mind and posture when researchers compared the same tasks on land and in chest-deep water. The group made far fewer errors on an auditory vigilance task in the pool,...

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Byline: ARGO.net Editorial Team
Published: 2026-08-14T11:35:02+00:00
Categories: Explainer, Humans

![Older swimmer wearing goggles at a pool](https://www.argo.net/wp-content/uploads/2026/08/older_swimmer_wearing_goggles_at_a_pool.jpg)

Twenty-one healthy older adults in their early seventies showed a striking split between mind and posture when researchers compared the same tasks on land and in chest-deep water. The group made far fewer errors on an auditory vigilance task in the pool, yet their standing-balance measures moved in the opposite direction, with water placing extra demands on postural control instead of reducing them.

The results come from a [Journal study](https://pubmed.ncbi.nlm.nih.gov/29738406) in the **Journal of Geriatric Physical Therapy**, where the volunteers completed attention and balance tasks alone and together in both settings. On the listening task, average errors were **111 percent higher on land** than in water during the single-task condition, 4.0 versus 1.9. For posture, **sample entropy**, a measure the authors used to describe sway complexity, was **100 percent higher in water** than on land.

The paper points to a practical idea for aquatic therapy. Partial immersion may help older adults hold attention during a simple monitoring task, while the water still forces the body to solve a harder balance problem. That pairing could matter for rehabilitation and exercise programs that want to work on mental focus and upright control in the same session, as long as instructors stay careful about what the study did and did not measure.

## The same people were tested in both environments

The experiment used a within-subject design, which means each participant served as his or her own comparison. The group had a mean age of **71.6 years** and every person completed the cognitive task and the balance task on land and again in chest-deep water. They also performed the tasks separately and at the same time, giving the researchers single-task and dual-task conditions to compare.

The cognitive test was an **auditory vigilance task** that counted listening errors. The motor test examined standing balance through center-of-pressure measures and sample entropy. Those outcomes matter because they capture different parts of the problem: one asks whether a person can sustain attention to incoming information, while the other asks how the body keeps itself upright when the support surface and surrounding forces change.

A detail worth keeping in view is that the article title uses the phrase episodic memory, while the abstract details center on an auditory vigilance task and balance outcomes. The reported numerical results in the abstract are about listening errors and postural measures, so those are the claims that can be stated with confidence here.

## Water reduced vigilance errors and the margin was large

The cleanest numerical finding was on attention. During the single-task condition, participants made 4.0 listening errors on average on land, compared with 1.9 in chest-deep water. Because the land value was a little more than double the water value, the authors reported that listening errors were **111 percent greater during land** than during water, with a reported **P value of.03**.

That result lines up with earlier aquatic cognition work cited around this study, including a younger-adult dual-task paper in [Physiotherapy Research International](https://doi.org/10.1002/pri.1628). The older-adult study was designed in part to test whether the same basic pattern would still appear later in life and on the vigilance measure it did. The pool setting was linked to fewer errors, not just a tiny statistical wobble.

Several mechanisms could help explain that pattern, although the paper does not isolate one cause. Water immersion changes pressure on the body, alters sensory input from the skin and joints and can shift blood distribution in ways that may influence alertness and comfort. A physiology paper in the [American Journal of Physiology-Regulatory, Integrative and Comparative Physiology](https://doi.org/10.1152/ajpregu.00516.2013) has described how water immersion can affect cerebral perfusion, which offers one plausible background pathway without proving that it drove this result.

The important caution is that fewer listening errors in a pool do not mean every part of cognition improved. The study did not show broader reasoning gains, long-term memory gains, or durable daily-life benefits. It showed one specific attention outcome in one small group under controlled test conditions.

## Balance became more demanding in the pool

The posture findings moved the other way. Sample entropy was 0.04 in water and 0.02 on land during the single-task condition, a **100 percent increase in water** with **P<.001**. The authors also wrote that **center of pressure area** and **center of pressure velocity** followed the same trend across environments.

Those numbers should be read carefully. The abstract does not say that immersion damaged balance or made participants unsafe. Instead, the authors concluded that partial aquatic immersion could be a useful way to **challenge cognitive and motor abilities** in older adults. In practical terms, the water appears to have helped the vigilance task while also making the body work harder to organize standing control.

That interpretation also fits earlier balance research from the same broad line of work. A prior article in the [Journal of Geriatric Physical Therapy](https://doi.org/10.1519/JPT.0000000000000081) reported that age-related postural sway changes were not consistent between land and aquatic environments. Water supports body weight, yet it also adds buoyancy, drag and constant fluid movement around the body, so the balance problem changes rather than simply fading away.

For therapists, the practical point is concrete. A chest-deep pool can reduce joint loading and still present a rich control task for the nervous system. A person may feel lighter while the postural system faces more variable sensory and mechanical demands.

## Doing both tasks together did not add a clear extra penalty

One of the more interesting parts of the paper is what did not change. None of the reported measures were significantly different between the single-task and dual-task conditions, with **P>.05** for those comparisons. The older adults did not show a clear extra drop in performance when they had to combine the listening and balance tasks.

That outcome trims back a tempting story line. It would be easy to assume that mixing attention and posture in water must overload older adults, but the reported data did not support that conclusion in this sample. The stronger pattern came from the environment itself, land versus water, rather than from a sharp added cost of multitasking.

Still, a null dual-task result does not prove that all combined pool activities are equally manageable. The study used a specific vigilance task and a specific standing setup, not open-ended conversation, obstacle negotiation, or fast reactive stepping. Small studies can also miss subtle effects, especially when individual differences are wide.

Broader evidence on aquatic exercise in later life, including a [BMC Geriatrics meta-analysis](https://doi.org/10.1186/s12877-020-01702-9), suggests that water-based programs can support balance-related outcomes in older adults. This experiment adds a narrower point: the immediate pool environment can alter attention and posture in different directions during the same session.

## What the study can support and what it cannot

The main strength here is precision. The researchers tested the same 21 people in both environments, used direct numerical outcome measures and reported clear land-versus-water contrasts. That gives the study more value than a casual observation that people seem calmer or more focused in a pool.

The main limits are just as clear. This was a small sample of healthy older adults, not a clinical trial in people with dementia, stroke, Parkinson's disease, or a recent fall history. The paper also does not show whether the vigilance advantage lasts beyond the session, whether repeated pool exposure changes the effect, or whether the same pattern appears in deeper water, colder water, or during moving exercises.

Another limit is scope. The reported cognitive outcome was a listening-error count from an auditory vigilance task, so it should not be stretched into a claim that chest-deep water broadly improves memory. The article's own title and indexing language reach wider than the abstract's numerical detail, which makes cautious wording especially important.

Even with those limits, the study offers a useful design clue for rehabilitation. A pool session may be able to pair lower-impact movement with a meaningful attentional task while keeping postural demands alive. For some older adults, that combination could help trainers and therapists build sessions that are physically gentler on joints yet still mentally and mechanically engaging.