Being “high” most commonly refers to the altered mental and physical state caused by cannabis (marijuana). It affects your thinking, perception, coordination, and mood, and the experience can last anywhere from one to several hours depending on how you consumed it. While cannabis is the most common context, feeling “high” can also describe other states, including dangerously elevated blood sugar or blood pressure.
What Happens in Your Brain
Cannabis produces a high by hijacking a system your body already uses to regulate itself. Your brain has a network of receptors called CB1 receptors, and they outnumber many other receptor types in the brain. Normally, these receptors act like traffic controllers, adjusting the activity of other chemical messengers to regulate things like hunger, temperature, alertness, and mood. THC, the main psychoactive compound in cannabis, binds to these same receptors and essentially overrides the system, turning dials your brain usually manages on its own.
This is why being high affects so many different functions at once. It’s not hitting one narrow target. It’s flooding a regulatory system that touches nearly every other system in the brain.
What Being High Feels Like
The experience varies from person to person and even from one session to the next, but certain effects are consistent. Cannabis has an immediate impact on thinking, attention, memory, coordination, movement, and time perception. Minutes can feel like hours. Short-term memory gets unreliable, so you might lose track of a sentence halfway through saying it. Coordination slows, which is why driving while high is dangerous.
Physically, cannabis causes your heart to beat faster and your blood pressure to rise. Your eyes often turn red because blood vessels in the eye dilate. Many people feel a dry mouth and increased appetite. The “euphoria” people associate with being high comes from a surge of the brain’s reward chemicals triggered by THC binding to those CB1 receptors.
Not everyone finds the experience pleasant. Some people feel anxious, paranoid, or uncomfortably self-conscious, especially with higher doses or less experience. The same biological mechanism that creates relaxation in one person can create racing thoughts in another.
How Long It Lasts
The timeline depends almost entirely on how the cannabis enters your body. When smoked or vaped, effects typically begin within minutes and peak around 30 minutes, with the overall experience fading over one to three hours. Edibles are a different story. They take 30 minutes to two hours before you feel anything, which is why people sometimes eat more thinking the first dose didn’t work.
Edibles also produce intoxicating effects that last longer than expected. The duration depends on how much you ate, whether your stomach was empty, and whether you consumed alcohol or other substances at the same time. A strong edible high can last six hours or more, with lingering grogginess afterward. This unpredictability is a major reason edibles are involved in more emergency room visits related to cannabis than smoking is.
When “High” Means High Blood Sugar
If you or someone you know has diabetes, “being high” sometimes refers to hyperglycemia, or elevated blood sugar. Symptoms usually don’t appear until blood sugar climbs above 180 to 200 mg/dL. Early signs include frequent urination, increased thirst, blurred vision, and unusual fatigue.
If blood sugar stays elevated, the body starts producing toxic acids called ketones. This condition, ketoacidosis, causes fruity-smelling breath, nausea, abdominal pain, confusion, and potentially loss of consciousness. Blood sugar above 240 mg/dL with ketone symptoms is a medical emergency.
When “High” Means High Blood Pressure
Most people with high blood pressure feel nothing at all, which is why it’s called a “silent” condition. But when blood pressure spikes to extreme levels (180/120 or higher), symptoms can appear suddenly: severe headache, chest pain, vision changes, dizziness, confusion, or signs of stroke like facial drooping or slurred speech. This is a hypertensive emergency and requires calling 911 immediately.
For pregnant individuals, the threshold is lower. Blood pressure of 160/110 or higher with symptoms warrants emergency help right away.