Walking an hour a day

Maria thinks that her friend's suggestion is quite good actually and decides to take her up on it. She starts walking one hour per day, in a park nearby her house. She even read somewhere that light intesity activity such as walking, or light swimming, doing Yoga or pilates, could have a benefit for her health and motivate her to increase her physical activity, have a positive impact on her effort to lose some weight and even enhance her mood and improve her quality of sleep. All these could even prove beneficial to her pain, also. 

She thinks she will be able to keep up with her walking. But during summertime, when there is a heatwave, walking could become less pleasant or even have risks for her health. She has had some problems in the past during heatwaves and is a bit skeptical. How she will manage.