# Sixteen cancer patients completed 16 sessions of coastal walking, swimming and snorkeling on the Costa Brava, then reported less tension and anger with more energy, suggesting relief can begin far beyond the oncology clinic

> Sixteen people living with cancer completed a 16-session program built around the sea and the clearest changes appeared in how they felt afterward. Their mood surveys showed lower tension and anger plus higher vigor after the blue-space sessions, giving researchers a concrete...

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Published: 2026-08-05T21:10:03+00:00
Categories: Explainer, Health

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Sixteen people living with cancer completed a 16-session program built around the sea and the clearest changes appeared in how they felt afterward. Their mood surveys showed lower **tension and anger** plus higher **vigor** after the blue-space sessions, giving researchers a concrete sign that a small coastal program may help patients recover moments of ease during an illness that often presses into every part of daily life.

The study, published in [**Heliyon**](https://pmc.ncbi.nlm.nih.gov/articles/PMC10362171) and indexed by [PubMed](https://pubmed.ncbi.nlm.nih.gov/37483694/), followed patients in Catalonia who alternated between time in or beside the sea and sessions spent resting in a quiet indoor room. Researchers tracked **blood pressure**, heart rate, sleep quality and mood so they could compare a simple blue prescription with a low-stimulation control rather than relying on a vague sense that a beach visit feels good.

The work came from the [University of Girona record](https://recerca.udg.edu/ca/publications/blue-prescription-a-pilot-study-of-health-benefits-for-oncologica/) for the project and from the [Oceans and Human Health program](https://oceanshealth.icm.csic.es/en/recreational-activities-at-sea-and-cancer.html) that helped organize it. Their shared question was straightforward: can carefully supervised contact with the sea give oncology patients measurable support between medical appointments, without presenting itself as a replacement for treatment?

## Why the researchers looked to the coast

Cancer often leaves patients dealing with fatigue, worry, disrupted routines and a body that no longer feels predictable. Many rehabilitation and survivorship programs already use exercise, support groups or green outdoor spaces to improve well-being. The researchers behind this study wanted to test whether **blue spaces** could offer something similar for oncology patients, especially in a coastal region where the sea is close enough to become part of routine care instead of a rare excursion.

The project took place during the summers of 2020 and 2021 in Roses and Tossa de Mar on the **Costa Brava**. Recruitment involved local medical centers, the **Catalan Institute of Oncology** and a patient association in Roses. That setup matters because the program was not built as a tourism experience. It was organized as a supervised health study with screening, physician involvement and clear inclusion rules.

European researchers have also spent years examining how contact with water affects health in the wider population. The European Commission's [BlueHealth program](https://bluehealth2020.eu/) describes blue spaces as outdoor environments where water is a central feature and where people can benefit by being near it, in it or on it. The cancer study extended that larger idea into a more demanding setting where patients may need support that feels restorative, manageable and socially safe.

## How the 16-session blue prescription worked

Participants rotated through four kinds of sessions. They walked along the seafront, spent time bathing or swimming from the beach, snorkeled with masks and support and also completed **control sessions** indoors while resting in a quiet room. Each activity was carried out four times for about 30 minutes, which produced a full program of 16 sessions.

Supervision stayed tight throughout the study. Researchers and physicians accompanied the patients and snorkeling sessions also included diving instructors. That level of support kept the intervention practical for people dealing with cancer histories and changing physical capacity. It also reduced the chance that any effect would simply come from one risky or exhausting outing rather than from a repeatable format that clinics could realistically adapt.

The methods mixed subjective and objective measures. The team used **smartwatches**, sphygmomanometers and the **Profile of Mood States** questionnaire. The questionnaire captured emotional changes such as tension, anger and vigor, while the devices tracked physiological indicators and sleep-related measures. Putting those tools together let the researchers compare what patients reported with what the instruments detected.

## What changed most after the sea sessions

The strongest pattern appeared in the mood scores rather than in the device readouts. Across the program, the paper reported a gradient of better results as participants moved toward greater exposure to a blue space. The authors wrote that exposure to blue spaces contributed to lower tension and anger while improving the vigor mood state of oncology patients.

Those findings fit the practical design of the activities. Walking by the coast asked little from the body while keeping the sea in view. Bathing sessions allowed patients to relax or swim gently. Snorkeling added novelty and close observation of the marine environment without demanding intense athletic output. Each activity gave participants focused time away from hospital routines and from the constant mental framing of illness.

The result does not mean every person responded in the same way or that each blue activity produced identical gains. The paper describes an overall direction rather than a miracle outcome. Even so, an improvement in **mental well-being** is not trivial for cancer care. A support program that reliably reduces distress for part of the week can change how patients experience recovery, follow-up care and their own sense of capacity.

## Why the watches stayed quieter than the questionnaires

The study did not find the same kind of clear separation in the smartwatch data. Researchers reported no significant differences between activities in the measurements gathered by the devices. Heart rate also did not rise significantly after beach and snorkeling sessions when compared with the control condition, which suggests the sea activities were broadly compatible with a relaxed pace.

That split between questionnaire results and device results is useful rather than disappointing. Supportive care does not need to produce dramatic physiological swings to matter. If a patient finishes a session feeling calmer, less angry and more energized, that change still has value even when a wearable device does not show a large statistical signal. Mood can improve through attention, scenery, social context and a sense of agency that may not map neatly onto one biometric measure.

The authors also worked with a small sample, so the study was built to explore feasibility and early signals rather than to settle every clinical question. Sixteen participants are enough to show whether the program can run safely and whether certain outcomes look promising. They are not enough to prove how strong the benefit is across all cancer populations, disease stages or treatment histories.

## What the study can mean for oncology care

The most realistic reading is that a short **blue prescription** could become one more tool in **supportive cancer care**. It would sit beside established treatment, rehabilitation and psychosocial support, giving patients a structured way to spend time outdoors with professional oversight. Coastal regions have a practical advantage here because the sea is already part of the local environment, so the intervention does not require a specialized clinic building.

Doctors and program planners would still need to decide who can participate safely, what level of exertion is appropriate and how often the sessions should run. The study excluded people whose medical condition or fear of swimming made sea activities unsuitable. A wider rollout would need the same caution, plus larger trials that test different cancer populations and compare blue-space support with other kinds of post-treatment activity.

The paper's broader contribution is conceptual as much as clinical. It treats the coast as part of a health setting instead of treating health support as something that happens only inside a room. For patients whose weeks are filled with tests, waiting and recovery, a supervised session in the sea or along the shore may offer a form of **restorative care** that is simple, local and measurable enough to deserve further study.