Research has shown that juggling directly leads to changes in the human brain. Adults who learned how to juggle influenced the volume of gray matter in the parts of the brain that process and store information dealing with perception. They also showed that neurones were expanding and making more connections with other neurones when new skills were learned.
Is it a possibility that juggling influences the pineal gland? We know from old wall paintings that juggling is an ancient tradition. It deals with those typical aspects that might be very important to stimulate the pineal gland. Attention, focus, concentration, cooperation, coordination and timing. This practice also calms the mind and balances your body and it gives you the possibility to understand the laws of gravity.
Juggling gives you that burst of energy to fight a bad habit or just to feel better. You can practice anywhere and anytime. You burn calories and have fun at the same time. I would describe it as active meditation or play with space and there is no competition involved.