Voyez à quel point le pouls peut changer.

Here voyez is most naturally the imperative form of voir, so it means something like see, notice, or observe.

In English, this kind of imperative is often used in explanations or demonstrations:

• See how much the pulse can change.
• Notice to what extent the pulse can change.

So it is not necessarily about physically looking with your eyes; it can also mean understand from the evidence in front of you.

Because voyez is a conjugated form, while voir is the infinitive.

• voir = to see
• voyez = see! / you see

In this sentence, voyez is being used as a command or instruction, so French needs the imperative form, not the infinitive.

Voyez can address:

• vous singular formal: one person, politely
• vous plural: more than one person

So the sentence could be speaking:

• to one person formally, or
• to several people

If you wanted the informal singular tu version, it would be:

• Vois à quel point le pouls peut changer.

À quel point means to what extent, how much, or how greatly.

It is a common French expression used to show degree or intensity.

So:

• Voyez à quel point le pouls peut changer. means
• See how much the pulse can change.

Very often, English translates à quel point simply as how:

• Regarde à quel point c’est différent = Look how different it is

Because à quel point is a fixed French expression. You usually learn it as a whole chunk meaning to what extent or how much.

Literally, it contains:

• quel = what/which
• point = point
• à quel point = to what point

But in real usage, you should usually understand it idiomatically rather than word-for-word.

Le pouls means the pulse.

It refers to the rhythmic beating felt in the arteries, usually used as a sign of heart activity.

A useful note for learners:

• pouls is masculine, so it takes le
• the final -ls is not pronounced

So pouls is pronounced basically like poo.

French usually uses an article more often than English does.

So where English might say:

• pulse can change

French often says:

• le pouls peut changer

This does not necessarily mean one specific pulse. It can refer to the pulse in general.

French often uses the definite article this way for general ideas:

• Le chocolat est bon. = Chocolate is good.
• Le pouls peut changer. = Pulse can change / The pulse can change.

Peut changer means can change or may change.

It is made of:

• peut = can / is able to / may
  (3rd person singular of pouvoir)
• changer = to change

So:

• le pouls peut changer = the pulse can change

Because after a conjugated modal verb like pouvoir (can), French uses an infinitive.

So the structure is:

• peut changer = can change
• peut varier = can vary
• peut augmenter = can increase

This is similar to English:

• can change
• not can changes

It is closer to see in the sense of notice / realize / observe.

Compare:

• regardez = look
• voyez = see / notice / understand

In many contexts, English could still translate voyez naturally as look if the tone is instructional, but the French verb is still voir.

So this sentence suggests:

• Notice how much the pulse can change more than
• Look at the pulse

Yes, grammatically voyez can also be the present indicative form of vous voyez with the subject omitted in certain contexts.

So in theory it could mean:

• You see to what extent the pulse can change.

However, as a standalone sentence, it is usually read as an imperative:

• See how much the pulse can change.

Context would decide which interpretation is intended.

They are related, but not always interchangeable.

• combien often focuses more directly on how much / how many
• à quel point often emphasizes degree or extent

In this sentence, à quel point sounds natural because it highlights the degree of change:

• Voyez à quel point le pouls peut changer.
• See how greatly the pulse can change.

Using combien here would be less natural.

The structure is:

• Voyez = imperative verb
• à quel point = expression meaning to what extent / how much
• le pouls = subject of the subordinate clause
• peut changer = verb phrase

So the sentence works like this:

• See
• to what extent
• the pulse can change

In smoother English:

• See how much the pulse can change.

This sentence is already correct and natural, especially in explanatory or instructional contexts. But in everyday speech, people might also say:

• Regardez comme le pouls peut changer.
• Voyez comme le pouls peut changer.

These versions use comme in a more informal, speech-like way to mean how.

Still, à quel point is perfectly good French and often sounds a bit more explicit about degree.