Walking on sand burns twice as many calories as walking on firm ground according to this website!
This site has the information for you to calculate your calories burned on flat ground, based on your weight, speed, and distance…once you calculate that...add 20% to 50% for sand, snow, or hills.
it's always an estimate. no website can account for individual fitness and exertion.
even with a HRM, calculations are estimates. there are far too many factors involved to calculate precisely, and even individually, exertion can change from day to day and hour to hour.
short of locking ourselves in metabolic chambers indefinitely, it's all best guess.
The side effects of allergy medications keep some people from using them. Natural remedies can be a great alternative, but some are more effective than others.