The control group (CG) will not undergo treatment, which will be evaluated in the pre- and post-phase of the study. Participants assigned to this group will receive general advice on the positive effects of regular physical activity, and they will be given the guide of recommendations for the promotion of physical activity.

The experimental group (EG), after an initial evaluation, will be subjected to a physical training program based on the resistance training, for 12 weeks with 2 weekly sessions (Tuesday and Thursday), with a duration of 45 minutes per session. Once the intervention is finished, you will undergo a final evaluation again to see if there is a difference or not with the results obtained at the beginning. In addition to the resistance training intervention, the experimental group received a Mediterranean diet protocol.

Resistance training. Subjects assigned to the experimental group participated in resistance program twice a week (on Tuesdays and Thursdays) for a period of 12 weeks, totaling 24 sessions of 60 minutes each. Each session during this time was divided into three clearly differentiated parts: i) 5-minute warm-up comprised of a series of gentle, low-intensity exercises designed to gradually prepare the muscles and joints of older adults for the main exercise.

Mediterranean Diet. In addition to the resistance intervention, the experimental group received a Mediterranean diet protocol based on the study by Ismail et al. [34] with the following meal plan: i) carbohydrates constituted 50% of daily intake; ii) fats repre-sented 35%; and iii) proteins accounted for 15%.

This was measured using the 14-item Mediterranean Diet Adherence Questionnaire (MEDAS) questionnaire, developed by the Prevention with Mediterranean Diet (PREDIMED) researchers. The questionnaire consists of 12 queries regarding how often various foods are eaten and two additional questions concerning typical eating habits in Spain [35]. Each question could be answered with a score of either zero or one. The total possible score ranged from 0 to 14, with a total of 9 or higher signifying sufficient compliance with the Mediterranean diet.

To evaluate anxiety and depression levels, the Hospital Anxiety and Depression Scale (HADS) was used [36,37]. This instrument is frequently used in populations of older adults who are not institutionalized [38] and includes 14 questions, divided equally between anxiety (even questions) and depression (even questions). Items are scored on a scale of 0 to 3, resulting in a total score range of 0 to 21 for both anxiety and depression, with a higher number indicating a greater presence of symptoms.

Sleep quality

The Pittsburgh Sleep Quality Index (PSQI) [39,40], a widely recognized tool for the assessment of sleep quality, was the questionnaire selected for this task. The PSQI includes 19 self-report items and 5 additional items that must be completed by the participant's bed partner or roommate (the latter are used only to obtain clinical data). From these items, a global score is calculated and seven dimensions or areas are evaluated: sleep quality; time to fall asleep; sleep duration; sleep efficiency; problems during sleep; consumption of sleep medication; and daytime functioning problems. The total score on the PSQI ranges from 0 to 21, with higher scores indicating poor sleep quality.

The measurement of perceived stress was carried out using the Perceived Stress Scale (PSS) [41] in its version for the Spanish language [42], an instrument composed of 14 questions that determines the degree of stress felt in the last month. This questionnaire uses a response system based on a five-point scale (0 = never, 1 = almost never, 2 = occasionally, 3 = frequently, 4 = very frequently). To calculate the total score on the PSS, the response values for items 4, 5, 6, 7, 9, 10, and 13 are reversed (so that 0 becomes 4, 1 becomes 3, etc.) and Then all the items are added. The score ranges from 0-56, with a higher score on the scale indicating a higher level of perceived stress.