This one popped up today
My summary: Lactate is a fuel source that buffers hydrogen ions. Lactic acid was never the thing making your muscles tired - it’s the hydrogen ions. The heart uses lactate as its primary fuel source at higher intensities. Other muscles use lactate as well. When you train, you adapt to use more lactate - not to produce less of it. Lactate may also be a signaler molecule that triggers those adaptations from exercise. Ingesting specific forms of lactate may both provide another fuel source and trigger more/better adaptations.
More messenger chemicals!