Inside Exercise
by Glenn McConell · Inside Exercise
Long-form interviews with exercise physiology and metabolism researchers about their own published work, covering VO2max, mitochondrial adaptation, interval training, lactate, and cardiovascular response. Conducted by an academic, so claims get pushed on.
More resources on Cardio Training
Exercise Advice — Cardiac Exercise Research Group (CERG), NTNU
Exercise guidance from the Norwegian university lab that generated most of the 4x4 interval research. Includes a demonstration video, seven-week progressions, and a researcher-answered FAQ, so readers can run the 4x4 protocol at the correct heart-rate intensity. The 4x4 is the most-cited single HIIT session in the literature and is endlessly rewritten by longevity blogs and app funnels. This is the primary institutional page: the actual intensity anchor (90-95% HRmax), the recovery structure, and a researcher-written FAQ addressing safety and progression. Free, and it gives the learner a protocol they can execute correctly today.
From Polarized to Individually Optimized Endurance Training... in 5 Steps
Recorded lecture for the ACSM Northland regional chapter in which exercise physiologist Stephen Seiler walks through five steps of endurance training design, covering intensity distribution, session duration, and how hard intervals should be dosed against a large low-intensity base.
The Science of Running: How to Find Your Limit and Train to Maximize Your Performance
First half examines what actually limits endurance performance — VO2max, lactate handling, running economy, central fatigue. Second half converts that physiology into training design, arguing against treating zones and workout labels as fixed prescriptions.
Daniels' Running Formula, 4th Edition
Builds training around VDOT, a single fitness number derived from race performance that sets paces for easy, marathon, threshold, interval and repetition work. Covers season planning, workout construction, altitude and heat adjustments.
Physical Activity Guidelines for Americans, 2nd Edition
Federal guideline setting weekly aerobic dose at 150–300 minutes moderate or 75–150 minutes vigorous activity, with the dose-response evidence behind it, MET-based intensity definitions, and cardiovascular and mortality outcomes. Full PDF free. Settles the 'how much cardio, at what intensity, for what health return' question from the source rather than from a secondary summary. Defines moderate vs vigorous operationally (METs, talk test, %HRR), which is the foundation for any zone scheme.
Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training
Review synthesizing training logs of elite runners, cyclists, rowers and skiers, showing roughly 80 percent of sessions fall below lactate threshold. Examines interval prescription, session duration, and why threshold-heavy training underperforms across sports. The primary source behind nearly every 'zone 2' and '80/20' article written since. Gives the actual evidence — training-log data from world champions plus the interval-duration research — instead of the downstream summary.