The risk of ischemic stroke increases in advanced age, corresponding with a noted decrease in circulating insulin growth factor-1 (IGF-1). IGF-1 is a known neuroprotectant involved in embryonic development, neurogenesis, neurotransmission, cognition, and lifespan.
Clinically, several studies have shown that reduced levels of IGF-1 correlate with increased mortality rate, poorer functional outcomes, and increased morbidities following an ischemic stroke.
Ischemic strokes are highly prevalent in the elderly population and are a leading cause of mortality and morbidity worldwide. The risk of ischemic stroke increases in advanced age, corresponding with a noted decrease in circulating insulin growth ...
www.ncbi.nlm.nih.gov
Just one example of many^ Lots of paraplegic, dementia ridden +90 year olds drinking their "food" through a straw or a tube in their stomach while staring at a ceiling +12 hours of a day for years.
A big factor in the physical/mental/health differences between a 25 year old person in their prime and a frail and chronically ill senior is their levels of HGH/IGF-1 and sex hormones (testosterone/estradiol).