BACKGROUND:The analysis of exercise adherence belongs among the basic criteria for evaluation of the effi ciency of intervention exercise programs.OBJECTIVE: The aim of this study was to analyze the adherence of participants to the half year dance and step aerobics program. METHODS:The experimental group consisted of 47 women aged 40 to 65 years old who exercised three times per week for a period of six months. The participant's attendance sheets and their answers to two questions from the checklist were used for the evaluation of their adherence to the workouts. RESULTS:The mean value of the adherence of the whole group to the intervention exercise program was 70.43%. Mean values of the group gradually decreased from 85.39% to 68.35% during the fi rst four months of the intervention exercise program. In the last two months of the intervention, the adherence continued to decrease when the average values of their attendance were slightly under 60%. Compared to other months, these diff erences were statistically and logically signifi cant.CONCLUSIONS: Reasons for diff erent or possibly decreasing degrees of adherence to long lasting intervention exercise programs are mostly objective, e.g. health (55.17%), family (13.70%) and work (22.41%). Other reasons (8.62%) are based on psychological factors (motivational and personal characteristics), the off erings and attractiveness of the activities, which are closely associated to the current health status and movement experience of the individual. Even the group form of exercise does not guarantee a high rate of the participant's adherence.

Overall, total body water physiologically decreases with age, from 75% in new-borns to 56% and 47% in men and women older than 50, respectively (EFSA, 2010). In adults, it is reported that the deficit of 1-2% of body water decreases physical and mental performance by 20% (EFSA, 2010; Gopinathan, Pichan, & Sharma, 1988). Dehydration is especially common and dangerous for infants, young children and older adults. Children have a higher proportion of body water compared to adults; they are also less heat tolerant and more susceptible to dehydration (British Nutrition Foundation, 2016). Older people have, thanks to a combination of lower total body water content and decreased thirst sensitivity, increased risk of developing dehydration. Additionally, age-related poor renal function and the increased prevalence of kidney and urinary tract diseases are likely to increase dehydration risk (Hooper, Bunn, Jimoh, & Fairweather-Tait, 2014; National Academies of Sciences, Engineering, and Medicine, 2016). The risk of dehydration can also be enhanced with increased physical activity, especially in hot climates. Adequate intakes of water for the elderly,