Stretching helps maintain flexibility. We often overlook that in youth, when our muscles are healthier. But aging leads to a loss of flexibility in the muscles and tendons. Muscles shorten and don't function properly. That increases the risk for muscle cramps and pain, muscle damage, strains, joint pain, and falling, and it also makes it tough to get through daily activities, such as bending down to tie your shoes.
Jump up ^ Lees C, Hopkins J (2013). "Effect of aerobic exercise on cognition, academic achievement, and psychosocial function in children: a systematic review of randomized control trials". Prev Chronic Dis. 10: E174. doi:10.5888/pcd10.130010. PMC 3809922. PMID 24157077. This omission is relevant, given the evidence that aerobic-based physical activity generates structural changes in the brain, such as neurogenesis, angiogenesis, increased hippocampal volume, and connectivity (12,13). In children, a positive relationship between aerobic fitness, hippocampal volume, and memory has been found (12,13). ... Mental health outcomes included reduced depression and increased self-esteem, although no change was found in anxiety levels (18). ... This systematic review of the literature found that [aerobic physical activity (APA)] is positively associated with cognition, academic achievement, behavior, and psychosocial functioning outcomes. Importantly, Shephard also showed that curriculum time reassigned to APA still results in a measurable, albeit small, improvement in academic performance (24).  ... The actual aerobic-based activity does not appear to be a major factor; interventions used many different types of APA and found similar associations. In positive association studies, intensity of the aerobic activity was moderate to vigorous. The amount of time spent in APA varied significantly between studies; however, even as little as 45 minutes per week appeared to have a benefit.
Behind the seemingly uniform acute hormonal response to exercise, explaining the disturbance to the neuroendocrine system caused by OTS is not that simple. There are several similarities with other intensive and chronic stress situations. There is compelling evidence for the involvement of HPA axis abnormalities in chronic stress situations such as post-traumatic stress disorder17 and depression25 and probably also during NFO and OTS. In chronic stress situations, the number of ACTH and cortisol secretion pulses is increased, which is also reflected in elevated urinary cortisol production.25

Association of exercise type with sex in the MCT (a) and HIIT (b) groups. Data are presented as proportions of the total number of exercise sessions. Other type of endurance; treadmill, cross trainer, aerobics etc., Domestic activities; housework, gardening etc., Other: golf, bowling, horseback riding etc. *Significantly different from men (p < 0.05)
11. De Vries N. M., van Ravensberg C. D., Hobbelen J. S. M., Olde Rikkert M. G. M., Staal J. B., Nijhuis-van der Sanden M. W. G. Effects of physical exercise therapy on mobility, physical functioning, physical activity and quality of life in community-dwelling older adults with impaired mobility, physical disability and/or multi-morbidity: a meta-analysis. Ageing Research Reviews. 2012;11(1):136–149. doi: 10.1016/j.arr.2011.11.002. [PubMed] [Cross Ref]

The study that kicked off this whole seven-minute workout fad four years ago notes that the secret-sauce is to strategically work different major muscles groups (upper body, lower body, core) each time you do the workout. This allows for one major muscle group to rest while you work the next muscle group, resulting in a super-efficient, super-effective routine.
It is well known that exercise in the older population may prevent several diseases [1–4]. Reduced physical activity impairs the quality of life in elderly people with Alzheimer's Disease [4], Parkinson's Disease [5], and Depressive Disorders [6]. Moreover, musculoskeletal, cardiopulmonary, and cerebrovascular decline are associated with poor physical fitness because of the cumulative effects of illness, multiple drug intake, fatigue, and bed rest [7, 8]. The effects of physical activity and exercise programs on fitness and health-related quality of life (HRQOL) in elderly adults have been widely studied by several authors [9–11]. De Vries et al. [11] conducted a meta-analysis focusing on elderly patients with mobility problems and/or multimorbidity. Eighteen articles describing a wide variety of actions were analyzed. Most used a multicomponent training program focusing on the combination of strength, balance, and endurance training. In 9 of the 18 studies included, interventions were supervised by a physical therapist. Intensity of the intervention was not reported and the duration of the intervention varied from 5 weeks to 18 months. This meta-analysis concluded that, considering quality of life, the exercise versus no-exercise studies found no significant effects. High-intensity exercise appears to be somewhat more effective in improving physical functioning than low-intensity exercise. These positive effects are of great value in the patient population but the most effective type of intervention remains unclear. Brovold et al. [7] recently examined the effects of high-intensity training versus home-based exercise programs using the Norwegian Ullevaal Model [12] on a group of over-65-year-olds after discharge from hospital. These authors based their study on the Swedish Friskis-Svettis model [13] which was designed by Johan Holmsater for patients with coronaropathy to promote their return to work and everyday activities and improve their prognoses. This model includes three intervals of high intensity and two intervals of moderate intensity, each one lasting for 5 to 10 minutes. Included in each is coordination. Exercises consist of simple aerobic dance movements and involve the use of both upper and lower extremities to challenge postural control [13]. Exercise intensity was adjusted using the Borg Rating of Perceived Exertion (RPE) Scale. Moderate intensity was set between 11 and 13, and high intensity was set between 15 and 17 on the Borg Scale.