Stamina and Fatigue (FoMT)

Your energy level is made up of two counterparts in Harvest Moon: Friends of Mineral Town -- stamina and fatigue. Basically, your energy levels will determine how many times you can use your tools before you overwork your body.

Stamina
There are four stages of stamina; each time you deplete your stamina to a certain level, a short animation will play out, as an indication for how much stamina you have left. Once your stamina reaches 0%, you do not instantly pass out or be unable to work; you will still be able to use your tools, but your fatigue will begin to kick in.
 * 1) The player pulls out a handkerchief and wipes his face. - This indicates that you have 50% of your stamina left.
 * 2) The player slumps forward while standing. - This indicates that you have 20% of your stamina left.
 * 3) The player sits down on the ground for a second. -  This indicates that you have 5% of your stamina left.
 * 4) The player's face briefly turns a shade of blue, and he does a fainting animation. - This indicates that you have 0% of your stamina left.

Fatigue
Fatigue is literally the medical term for exhaustion, or lack of strength. Once your stamina is all used up, your fatigue will begin to build up. There are only two animations that indicate your level of fatigue. If you continue to work with a high fatigue level, you will eventually pass out.
 * 1) The player will stand with his hand to his temple while shaking his head, as if he has a bad headache. - This indicates your fatigue level is at about 50.
 * 2) The player will sit down; the animation is the same as stage three of stamina depletion, but your character will also turn blue until you replenish your energy. - This indicates that your fatigue level is at about 80, which is dangerously high.

Depletion
Using tools of any kind will deplete your stamina/rack up fatigue. This includes tools like the Milker, Shears and Brush. For the upgradable tools (i.e. Hammer, Axe, etc.) the higher level tool you have equipped, the more energy is used up per use.

Repletion
Fortunately, there are numerous ways to replenish your energy. Resting and eating are the main ways to do so.

Rest
Sleeping in your bed is one of the best ways to regain your energy. The more hours you sleep (i.e. the earlier you go to bed), the more energy will be recovered.

Foods
Almost all foods you eat play a part in your stamina/fatigue levels in one way or another. Some will regain, but others are actually harmful to you and use up your energy. The "poisonous" foods are examples of such, like the Poisonous Mushroom, Red Grass or Burnt Foods.

Medicine
Clinic-bought medicine (or homemade) like the Bodigizers and Turbojolts also help replenish energy, but there are a lot of cheaper foods that have similar effects. (For example, a regular Bodigizer that costs 500 G will replenish 50 stamina, but Curry Noodles will recover 60 stamina and decrease your fatigue by 3, and the ingredients are considerably cheaper).

Hot Springs/Bath
You will regain a bit of stamina/fatigue for the time you spend in the Hot Spring or your own Bathroom.

Goddess Gem
After you collect all 9 Goddess Jewels, you will receive a Goddess Gem, which is an equippable tool that regains a bit of stamina as time passes (as long as it is equipped).

Increasing Maximum Stamina/Fatigue
The Power Berries and Blue Power Berry will increase your maximum stamina and fatigue tolerance respectively, making it possible to work longer without passing out.