"I have no motivation today."
Kaito slumped on the table.
Leo put down his book. "How does it feel?"
"Heavy. Everything feels bothersome."
Sora looked worried. "Since when?"
"Since morning. No, since last night."
Leo opened his notebook. "Mood fluctuations are related to brain chemicals."
"Chemicals?" Kaito looked up.
"Neurotransmitters. Substances that carry signals between brain cells."
Sora supplemented, "Like serotonin, dopamine, noradrenaline."
"I've heard of those," Kaito said. "Serotonin is the happiness hormone?"
"More accurately, it's involved in mood stability," Leo explained. "When serotonin decreases, you're prone to depressive mood."
Kaito asked, "So my serotonin is low?"
"It might be temporarily decreased," Leo answered. "But the cause is complex."
Sora asked, "What causes it to decrease?"
"Stress, sleep deprivation, lack of exercise, unbalanced nutrition," Leo listed.
Kaito thought. "All of those apply."
"Also, lack of sunlight affects it."
"Sunlight?"
"Serotonin production is promoted by sun exposure. When it's winter or cloudy days continue, mood tends to drop."
Sora understood. "Seasonal affective disorder."
"Yes. Especially common in areas with short daylight hours."
Kaito sighed. "If it's a brain problem, is there nothing I can do?"
"No, there are things you can do," Leo encouraged.
Sora asked, "For example?"
"First, exercise. Aerobic exercise increases serotonin."
"Exercise," Kaito looked reluctant.
"Walking is fine. Just 20 minutes of walking can change your mood."
Leo continued, "Next, rhythmic movement."
"Rhythmic movement?"
"Actions repeated at a steady rhythm. Walking, chewing, breathing."
Sora supplemented, "Rhythmic activities activate serotonin neurons."
"So chewing gum is also effective," Leo said.
Kaito showed some interest. "That's easy."
"Diet is also important," Leo continued. "An essential amino acid called tryptophan is the raw material for serotonin."
"What contains it?"
"Soybeans, bananas, nuts, fish."
Sora added, "But absorption improves when taken with carbohydrates."
"So like banana and bread?" Kaito asked.
"Ideal combination," Leo acknowledged.
"But," Sora said carefully, "food alone won't change things dramatically."
"Right. Mood is the sum of many factors," Leo agreed.
Kaito asked, "What else?"
"Social connection. Talking with people."
"I'm talking now," Kaito said.
"That's good too," Leo smiled. "Isolation worsens mood."
Sora offered another perspective. "There are cognitive factors too, right?"
"Of course," Leo nodded. "Thinking patterns affect mood."
"What do you mean?" Kaito asked.
"Negative thought patterns lower mood. Thinking 'nothing goes right' or 'I'm useless' also decreases serotonin."
Sora explained, "Brain and mind influence each other."
"Thoughts change chemicals?" Kaito was surprised.
"Yes. And vice versa," Leo answered. "Chemicals change thoughts."
Kaito pondered. "So which comes first?"
"The chicken-and-egg problem," Sora said. "They happen simultaneously."
Leo added, "That's why you approach from both sides. Lifestyle and thinking patterns."
Kaito asked, "What can I do right now?"
"Let's go outside," Leo suggested. "Let's walk together."
"Right now?"
"Right now. Get sunlight, move your body."
Sora stood up. "I'll come too."
Kaito slowly stood. "Will it really work?"
"Might not be instant," Leo said honestly. "But better than doing nothing."
"On down days, the brain is saying 'rest,'" Sora said.
"But you don't need to completely stop," Leo continued. "Move just a little. That's the first step to recovery."
The three went outside. It was cloudy, but some light was showing through.
"I feel a tiny bit lighter," Kaito said.
"Might be placebo effect," Leo laughed. "But that's also brain power."
Sora added, "Believing also changes chemicals."
Kaito took a deep breath. "The brain is mysterious."
"Mysterious, complex, but changeable," Leo said.
The three walked quietly. Heavy feet gradually became lighter.
Mood goes up and down like waves. But if you know how to ride the waves, you won't drown. Understanding brain activity is the first step to mental freedom.