Linda Gray has a ''gratitude walk'' every day after battling through polio as a child.

The 'Dallas' actress has written her memoir, 'The Road To Happiness is Always Under Construction', to celebrate her 75th birthday and has revealed her life-long love of exercise partly comes from her joy at beating the viral disease that can leave victims paralysed or with permanent walking difficulties.

She shared: ''I had polio and I was not expected to walk and that's why the book cover and that cover show my legs. A lot of it is I'm thrilled I can walk, so I take what I call my gratitude walk. Gratitude walk is going outside, I love to be outside, and I walk for as long as that day allows. Maybe it's 15, maybe it's 20 minutes. Longer days, weekends, maybe half hour, an hour, 45 minutes. We start early in the morning, go outside ... I never ever miss my gratitude walk.''

Linda has maintained a positive mental attitude throughout her life, despite being presented with numerous challenges such as a turbulent childhood with an alcoholic mother, and living through an emotionally abusive marriage to Ed Thrasher which eventually ended in a bitter divorce.

The small screen icon considers her problems to have been just ''speed bumps'' in the road and she never let any of her difficulties get the better of her.

Speaking on 'This Morning', she said: ''It took a lot to be on a world renowned series and then go through the things I do in my private life. So there are not a lot of pretty things that I had to experience but they are speed bumps. I had a choice, I could think negatively about my life or I could move forward and think positively , and that's what I did.''