This is surprising because… well, we’re just sitting and the vehicle’s doing the work, right?

But:

  • Vehicles accelerate, brake, bump, turn, vibrate, … and our muscles micro-adjust continously so we sit upright. Over hours hours, that’s a lot of energy.
  • We feel like we’re still. But the inner-ear fluids, eyes, etc. constantly get feedback about motion. That mentally drains us (and causes motion sickness).
  • Noise from vehicles, traffic, … triggers cortisol, a stress hormone. That drains us.
  • Sitting in one place restricts blood flow and it pools in our legs, making the heart work harder.
  • In flights, the air pressure is low, lowering oxygen levels. The dehydration thickens our blood, making pumping harder.

What helps is:

  • Noise-cancelling headphones (reduces the rumbling / traffing sounds)
  • Compression socks (reduce blood pooling in the feet)
  • Eye masks
  • Good back support

… and the usual good habits:

  • Drink water
  • Exercise
  • Fasting / eating light
  • Breathe slowly