In her book Positivity, Barbara L. Fredrickson writes, “You are constantly changing — not just your clothes or your hairstyle, but your inner core, the very essence of your being. Change is the rule, constancy the rare exception. Consider the change underway within you at this very moment. What you know as ‘you’ is actually trillions of cells living and working together. Most only live for a few weeks or months. When they die, they are replaced by new cells. This cycle continues for as long as you live. The pace of cell renewal varies by body part. Your taste buds live only a few hours. Your white blood cells live about ten days. Your muscle cells live about three months. Even your bones are made anew time and again. Considering these differences, scientists have suggested that you replace about 1 per cent of your cells each day. That’s 1 per cent today, another 1 per cent tomorrow, amounting to roughly 30 per cent by next month and 100 per cent by next season. Seeing yourself and your cells in this way, every three months you get a whole new you. Perhaps it’s no coincidence that it takes around three months to learn a new habit or make a lifestyle change. Perhaps we can’t teach an old cell new tricks.” Continue reading