The Quantified Self is a movement to incorporate technology into data acquisition focusing on person's daily life, in areas such as nutrition, sports, sleep and mood. Self-monitoring is usually done with wearable sensors and smartphone apps.
Biohacking means realtime self-experiments, such as changes to your daily nutrition, and following how these changes affect different markers. Biohacking is experimentation and Quantified Self is about tracking, so they go well hand in hand.
I'm the co-founder of Quantified Self & Biohacking Finland. It is a community that organizes events and brings likeminded individuals and companies together in the capital region of Finland.