6km/h is a brisk walk. You need to concentrate on the walking aspect if you want to maintain that pace. Slow down a bit to 4-5km/h and you can last much longer

6km/h is a brisk walk. You need to concentrate on the walking aspect if you want to maintain that pace. Slow down a bit to 4-5km/h and you can last much longer, not to mention multitask more effectively (listen to an audiobook, be on a phone call, just brainstorm, etc.) so you don't actually need to set aside hours a day specifically for walking.