Your own mouth is the intensity monitor.
Try to talk while you move. What comes out tells you exactly how hard you are working. Three states, and that is the whole system.
The Energy Tank, from the outside
The Energy Tank showed you those three systems from the inside. The Talk Test is how you read them from the outside, standing on a levee path, with nothing strapped to you.
No monitor. No formula. No math. You already carry the equipment.
Read the talking. Name the state.
That was Task 1. Task 2 runs the other direction.
In Task 1 you heard the talking and named the state. That is the skill you use mid walk, when you want to know what you are actually doing.
Task 2 is the one you use before you leave the house. Felicia has three sessions this week and a different goal for each. You pick the talking she should be able to hold in each one.
Two things change
The guide card is gone. And each state goes to exactly one session, so if a state is already spoken for, the app will tell you where it is rather than moving it for you.
Three goals. Pick the talking that gets each one.
What you take with you
Full sentences is the easy end and it should be most of your week. Short sentences is the line, and holding it is what builds the engine. Barely a word is a short visit, on purpose.
Say a sentence out loud once in the middle of anything. That is the whole test.
While you are out there
Full-sentence pace is the one you can hold the longest, so it is the pace that runs long. Eating during a session only starts to matter around the one hour mark. Under that, water covers it. Around an hour, a small amount of carbohydrate starts to help, and for two to three hour efforts the working guideline is up to about 60 grams an hour, which is a bit more than two medium bananas at about 27 grams of carbohydrate each.
Why this works
Breathing changes before anything else you can feel does. Speech is what breaks first.
Sources: Persinger et al., Medicine and Science in Sports and Exercise, 2004 (speech difficulty at ventilatory threshold, treadmill and cycle). Foster et al., Journal of Cardiopulmonary Rehabilitation and Prevention, 2008 (talk test tracks a moved threshold). Vieira et al., Reviews in Cardiovascular Medicine, 2022 (systematic review, 10 studies, 414 participants). Ballweg et al., Journal of Sports Science and Medicine, 2013 (talk test overestimates the gas-exchange thresholds). Reed and Pipe, Current Opinion in Cardiology, 2014 (practicality, mode independence, poor fit for interval work). Tanaka et al., Journal of the American College of Cardiology, 2001 (age-predicted maximal heart rate revisited). Brooks and Mercier, Journal of Applied Physiology, 1994 (crossover concept, fat and carbohydrate by intensity). Jeukendrup, Sports Medicine, 2014 (carbohydrate intake during exercise by duration). Banana portion from USDA FoodData Central, Bananas raw, FDC ID 173944, 22.84 g carbohydrate per 100 g, USDA medium portion 118 g. All content is placeholder pending expert review.