What makes you strong?

I was having a surprisingly deep conversation with a lovely colleague, in the office cafeteria the other day, when she asked me:

What makes you strong?

This question was clearly on the back of a conversation where we were both talking about some of the tough stuff that had come our way. We had similar views on priorities and the importance of certain things, yet we had different issues to cope with and different personalities to deal with it.
The question was a good one. One that I had not given much thought to.

I really didn't know the answer. Even after pondering for a few days, I had still not come up with an answer. I then began asking others for insights and inspiration. Here are a few of their ideas.

Walking in nature
Making a difference in someone else's life
Being believed in by good people
Confidence in myself
Physical exercise

It's a good list, but it's still wasn't obvious what mine were.
Do you know what makes you strong in the tough times? What keeps you strong for everyday? Have you ever thought about it? 

So after a bit of thinking, here is my list.
1. Physical fitness
2. Being with my husband
3. Plenty of sleep

So if you ever hear of me running marathons, sleeping all weekend then only hanging out with my husband, you will know I am in seroious need of some help!