Studying the effects of diver training on wellbeing.

"Understanding the impact of this phase can provide valuable insights."

  • We monitored the overall health, fatigue and sleep levels of 10 trainee divers on a particularly demanding part of their course.
  • Results showed positive changes in body composition but also severe fatigue, poor sleep quality and sub-optimal nutritional choices.
  • We recommended continuing to monitor fatigue and health, and providing education about the benefits of a healthy lifestyle to maximise performance.

Operational diving roles are some of the most physically demanding within the RNZN. The Mine Counter Measures (MCM) phase of Able Diver training is particularly challenging. The aim of this study was to better understand the impacts of this training phase on diver trainee wellbeing, which in turn will inform future course delivery and trainee support.


We monitored 10 trainee divers throughout a 14-week RNZN MCM course.

Initially, each diver completed:

  • the MOS-36 health questionnaire
  • an anthropometric assessment
  • the Diver Health Survey (DHS)
  • a 4-day food diary.

Throughout the course, each diver reported their levels of fatigue using the Samn-Perelli fatigue scale and completed the DHS. We recorded out-of-water physical activity and nightly sleep via actigraphy. In weeks 6 and 10 divers completed another food diary and at the end of the course we repeated the anthropometric assessment.


Across the group:

  • baseline wellbeing scores (MOS-36) were typically high
  • in most cases, DHS scores were below the threshold score for decompression sickness
  • Samn-Perelli fatigue scores were routinely high
  • estimated daily energy expenditure was high
  • eight divers decreased their body mass and all divers reduced body fat percentage, indicating a shift in body type to a more muscular/athletic build
  • divers typically achieved less than recommended levels of sleep
  • poor weekend nutritional habits were observed.


The study findings highlighted the benefits of a holistic approach to the monitoring of health and performance in this and similarly demanding military roles. We observed positive changes in body type but also severe fatigue, poor sleep quality, and suboptimal nutritional choices.

Alongside continuing to monitor fatigue and health, we recommended providing education about the benefits of a healthy lifestyle to promote wellbeing and maximise performance. The RNZN introduced such a programme in 2017 in response to our study’s findings.