A Chinese friend of mine learned about my discovery that it was much easier to study Chinese while walking on a treadmill than sitting. This led her to buy a treadmill. She began to study English (e.g., GRE vocabulary words) while walking on the treadmill. “It worked very well,” she told me. She found that if she studied words while walking, she could remember them four days later. If she studied them sitting down, she could remember them only a day later. With Anki, the default settings assume you can only remember what you’ve studied for a day — the first time you learn a word, you will be tested a day later.
This reminds me of Allen Neuringer’s finding of better memory for material learned while moving, but the size of the effect my friend observed is still shocking. If you can remember words four times longer before you need to review them, you can learn four times as fast. The effect that Jeremy Howard and I observed was of similar size. We could only study 10 minutes sitting down but could easily study for 40 minutes or more while walking.