Oh, Anna, dear,
Just because you didn't see or notice any changes in walking 4 KM a day, does not mean big changes were absent. Notice the benefits listed in research from Harvard Medical School that you were probably not observing: (Sorry for the long quote)
More than 2,400 years ago, Hippocrates said, "Walking is a man's best medicine." To find out if he was right, two scientists from University College London performed a meta-analysis of research published between 1970 and 2007 in peer-reviewed English-language journals. After sifting through 4,295 articles, they identified 18 studies that met their high standards for quality. In all, these studies evaluated 459,833 participants who were free of cardiovascular disease when the investigations began. Each of the studies collected information about the participants' walking habits along with information about cardiovascular risk factors, including — in most studies — age, smoking, and alcohol use and, in many cases, additional health data as well. The participants were tracked for an average of 11.3 years, during which cardiovascular events (angina, heart attack, heart failure, coronary artery bypass surgery, angioplasty, and stroke) and deaths were recorded.
The meta-analysis makes a strong case for walking. In all, walking reduced the risk of cardiovascular events by 31%, and it cut the risk of dying during the study period by 32%. These benefits were equally robust in men and women. Protection was evident even at distances of just 5½ miles per week and at a pace as casual as about 2 miles per hour. The people who walked longer distances, walked at a faster pace, or both enjoyed the greatest protection.
This meta-analysis included studies from seven countries on three continents. At the risk of being chauvinistic, here is a brief summary of three Harvard studies of walking and cardiovascular health:
- Among 10,269 male graduates of Harvard College, walking at least nine miles a week was linked to a 22% lower death rate.
- Among 44,452 male health professionals, walking at least 30 minutes a day was linked to an 18% lower risk of coronary artery disease.
- Among 72,488 female nurses, walking at least three hours a week was linked to a 35% lower risk of heart attack and cardiac death and a 34% lower risk of stroke.
http://www.health.harvard.edu/newsletter_article/Walking-Your-steps-to-health
And, if I am reading your post correctly, you recently increased your level of exercise up to the aerobic, you really feel the benefits. Remember, the walking was a fantastic preparation and enabled you to effortlessly move up to another level.
Adding flexibility is another big plus.
Way to go!!!
