This is the final exam for Hormesis & the Dose-Response Curve. It pulls the whole course together: the three shapes a dose-response curve can take — linear-no-threshold, threshold, and hormetic — and how to read an optimum off a hump; why a biphasic, non-monotonic response makes “good vs bad” the wrong question; the biology of adaptive overcompensation — autophagy, heat-shock proteins, mitohormesis, and immune training that overshoot baseline; why recovery is part of the dose and how allostatic load turns the same stress from builder into destroyer; the worked cases across exercise, fasting, vaccines, sunlight, the contested alcohol J-curve and radiation; and the honest limits — that hormesis is not a licence to self-poison and that so much of the evidence is confounded. The through-line is one picture: a curved response in a world that keeps trying to draw a straight line through it.
Several questions look easy until you spot the trap — that a J-curve proves drinking is healthy, that “a little of everything is good” so asbestos must have a safe dose, or that whatever doesn’t kill you makes you stronger. Reason each one through.
How this exam works
Read carefully — this exam is final. Each question appears one at a time. Once you submit an answer it is locked for good: there’s no going back, no retry, and no restart. Your score is hidden until the end, where you’ll see a pass/fail verdict. The pass mark is 70%. A few questions ask you to select all correct answers.
What does the word "hormesis" specifically mean?
Select an answer to continue.
Course Recap
Big picture
Hormesis & the dose-response curve, in one picture
- Hormesis & the Dose-Response Curve
- The shape of the curve
- Three shapes: linear-no-threshold (harm from the first molecule, no safe dose), threshold (safe up to a point), and hormetic/inverted-U (a beneficial region with an optimum). Read the optimum; "none is safest" and "more is better" both fail on a hump. Averages mislead on a curved response. The master skill is telling which shape you face.
- Adaptive overcompensation
- The engine: a mild stressor trips repair/defense that OVERSHOOTS baseline. Pathways — autophagy (recycling), heat-shock proteins (chaperones), mitohormesis (a ROS pulse as a signal that boosts antioxidant defenses), immune training, and xenohormesis (plant stress molecules). The overshoot happens during recovery.
- Hormesis in the wild
- Solid: exercise, brief fasting, vaccines, moderate sunlight — mechanism plus interventional evidence. Contested/confounded: the alcohol J-curve (sick-quitter effect) and radiation hormesis (LNT stays the regulatory default). Separate what you can dose and measure from what you can only correlate.
- Dose, frequency & recovery
- Recovery is part of the dose. Acute-intermittent-WITH-recovery builds (repair overshoots); chronic-relentless-with-no-recovery destroys (allostatic load — cumulative wear when adaptation never completes). Equal total stress, opposite outcomes, depending on structure.
- Transfer & honest limits
- The curve travels: forest fires, team workload, raising kids, software stress-testing. But hold its edges — NOT a licence to self-poison (asbestos/lead have no safe dose), "the dose makes the poison" cuts both ways (water/oxygen/sleep overdose), "what doesn't kill me" is often survivorship-biased and false, the optimum is personal, and much evidence is confounded.
- The shape of the curve
Key takeaways — the whole course
Hormesis says the biological response to a stressor is often biphasic: a low dose stimulates and strengthens while a high dose of the very same thing inhibits or harms — so the effect of X is a curved function of the dose, with an optimum in the middle. That reframes the instinctive question. “Is this good or bad?” has no answer on a hump; the real questions are which curve is this, how much, how often, with what recovery, and where on the curve am I? The strengthening comes from adaptive overcompensation — repair and defense (autophagy, heat-shock proteins, mitohormesis, immune training) that overshoot baseline during recovery, which is why recovery is part of the dose and why the same total stress builds when spaced and breaks when relentless (allostatic load). Some cases are solid (exercise, fasting, vaccines, sunlight); others are contested and confounded (the alcohol J-curve’s sick-quitter effect, radiation hormesis, where linear-no-threshold stays the regulatory default). And hold the model’s edges: it is not a licence to self-poison — many toxins have no safe dose — “the dose makes the poison” cuts both ways, “what doesn’t kill me makes me stronger” is often survivorship-biased and false, and the optimum is personal, not universal. Whenever someone hands you a verdict — “X is good for you,” “X is bad for you” — ask the question this course was built around: at what dose, how often, and where on the curve?