One of the ideas from Yoga I have found the most useful is Prana. A lot of Yogic philosophy boils down to metaphors or stories that help you create mental playbooks to approach life. I have spoken before about 'Neti Neti' or 'Not this, Not that', which is a way of distancing yourself from an emotion you are feeling. So, 'I am angry' simply becomes 'I am feeling angry'. It may seem like a superficial change, but feelings pass whereas we constantly attach to whatever we think we are. I am dot dot dot is dangerous and powerful. Prana is defined as 'life force' but can also be thought of as energy. I like to think of Einstein's comment that "Energy can neither be created nor destroyed, it can only be changed from one form to another".
Thinking of how you approach your day as how you approach your energy level is a fun thought experiment. When are you at your best? When you do something, does it add to your energy or draw from it. The yogic idea extends widely. It talks about the Prana you get from a tidy environment. It talks about Prana you get from food. It talks about the effect of being in traffic or crowds. Most of all it is a way of thinking of what you need 'to be'. Like the petrol that goes into a car, you may have a Ferrari, but if the tank is empty, it isn't going anywhere.
Various things add to your tank. Eating well. Getting exercise. Getting enough (but not too much) sleep. Proper times of relaxation. Even having productive stories to help you figure out how to approach the various challenges life throws at you, can add to your tank. Strong relationships, or even just knowing there are people who are thinking about you, and care for you, can add to your tank.
Then there are things that draw on your energy. That is not a problem. Stress is actually good in moderation because that is how we learn, and how we get things done. The important point is not to try be a hero. It doesn't matter who you are, and what you could potentially do. If you run out of energy, you are no good to anyone.
One of the most powerful ways of adding Prana is ridiculously simple. Learning to breathe properly. A big part of yoga that often gets ignored when taught in the West is the breathing exercises. We think you need to sweat or hurt for it to help. The Yogis link breath so closely to energy that the breathing exercises are called 'Pranayama' which literally translates as the 'extension of life force'. We know this. Think of the trick little kids are taught when they are angry. 'Take a breath, and count to ten'.
Life is better after a deep breath. Life is better with a buffer of Prana.