What is the key to longevity?
Researchers and doctors have been studying this for many years and a number of patterns has consistently shown to be true: It's a combination of nutrition, exercise and sleep. From a nutrition perspective, a predominantly plant-based diet is the way to go. The Mediterranean diet continues to outperform all other diets year after year. A plant-based diet can not only prevent disease but it can reverse cardiovascular illness and many others. We now also have enough evidence on the importance of movement, exercise and specifically a combination of resistance and endurance training. Muscle growth is not only positive for the muscles themselves but it also positively affects bone density (which we tend to lose as we age), as well as effects on your immune system, gut microbiome and even mental health. The positives are endless. Lastly, if we do not get proper sleep (typically 7-9hours/night), the other two factors, diet and exercise, will not be optimal. Consistency in going to sleep and waking up at the same time is crucial to overall wellbeing and recovery. 
Researchers of the Blue Zones argue that another crucial part to living healthily into old age is the social circle or community we are part of. 
If you want to live a long and healthy life, eat more plants, exercise, get some sleep and spend time with your friends and family.