RE-inventing Strategies for Healthy Ageing; Recommendations and Tools

The proportion of older individuals worldwide is growing, posing a significant challenge to western societies. To address the health challenges of the aging population, primary prevention efforts should focus on various lifestyle factors simultaneously. However, many interventions fail to maintain improved lifestyle habits among participants, highlighting the need for novel and complex approaches to ensure healthy aging among older adults.

The RESTART randomized controlled trial aims to investigate whether participants undergoing a complex lifestyle intervention improve their cardiorespiratory fitness, muscle strength, physical activity, adiposity and body composition, quality of life and cognitive function at 24 months, compared to active controls.

The study and data collection will occur in Tromsø, Norway (pop. 77,000). Participants will receive the intervention at a local community exercise center near the University of Tromsø campus area. Testing of physical performance will take place at the UiT Faculty of Health Sciences research laboratory for sports, physical activity, and public health. The Clinical Trial Unit (CTU) at the local university hospital will additionally oversee clinical examinations, collection of questionnaire data, and blood sampling.

At baseline, both the Control and Intervention Groups are given wrist-worn activity trackers and access to national physical activity recommendations. The Intervention Group also undergoes a comprehensive lifestyle program that includes high-intensity aerobic and strength exercises, as well as dietary and behavioral counseling. The Intervention Group is gradually introduced to exercise activities organized by Tromsø Municipality and local NGOs. Outcome testing is conducted at baseline, 6, 12, and 24 months, with the primary endpoint (VO2max) assessed at 24 months.

Intervention participants will be divided into 4 groups of 12-15 participants each and perform high-intensity training to target the cardiovascular system and skeletal muscle force-generating capacity. For 12 months, the intervention group performs supervised indoor cycling or outdoor hill interval training twice a week at a relatively high intensity (≥85% of maximal heart rate during 4x4 minutes) separated by active rest periods at approximately 70% of maximal heart rate. Immediately after the aerobic exercise, participants perform strength training (3 sets of 5 repetitions) involving leg-press, lateral pull-down, and chest press exercises, with an intensity corresponding to ≥80% of their maximal strength. From months 6-12, one of the two weekly exercise sessions will be led by the Healthy Life Center (HLC; "Frisklivssentralen"), enabling a transition to supervised exercise via the Tromsø municipality primary health care. Between month 12-18, the HLC continue to supervise the participants during one weekly exercise sessions, while they are additionally introduced to exercise activities arranged by local NGO:s.

From month 3 to 12, participants will receive behavioral counseling based on the Acceptance and Commitment Therapy (ACT) approach during six 2-hour group sessions. The individual approach aims to enhance participants' capacity to manage challenging cognitive and emotional experiences, foster psychological flexibility and distress tolerance skills, and promote the development of self-efficacy and new behavior patterns that align with their life values.

From month 6 to 12, the intervention group will receive four dietary counseling sessions based on Norwegian nutritional guidelines. Two individual sessions will involve food diaries, while two group sessions with a partner will focus on basic nutritional information and practical food preparation. The objective is to promote a healthy, sustainable, and personalized diet while promoting increased protein intake, reducing the consumption of high-energy-dense foods and drinks with low nutritional value.

Beginning from month 12 and onwards throughout the trial, the intervention group will be granted access to the Re-start eTool (https://re-start.no/), which is specifically tailored to older adults. The eTool offers concise and easy-to-understand articles, videos, and self-assessment tools that promote physical activity, healthy dietary habits, and behavioral strategies from the complex intervention. The Re-start eTool aims to provide support and reminders to participants as they gradually transition to independently maintaining the achieved lifestyle habits and physical capacity levels.

Throughout the study period, the intervention instructors and assessors monitor potential adverse events during the exercise and testing phases, and all adverse events are reported to the study coordinator. Measures to mitigate adverse events include: 1) insurance of participants via The Norwegian System of Patient Injury Compensation; 2) involving a MD with sports medicine specialization to ensure treatment of potential injuries; 3) pilot study experiences show that short-term alternative exercises are effective in managing exercise-induced pain and discomfort.